Method and device for controlling confined water in ship lock foundation pit based on soil shear strength

Abstract

The application discloses a ship lock foundation pit confined water control method and device based on soil body shearing strength, and relates to the technical field of ship lock engineering, wherein the method comprises the following steps: calculating the confined water head, the overlying impermeable layer thickness and the initial gushing safety coefficient according to the geological survey data and the foundation pit excavation bottom surface elevation; calculating the soil body shearing strength based on the pre-acquired cohesion and internal friction angle of the overlying impermeable layer soil body; and further calculating the corrected gushing stability safety coefficient. When the corrected gushing stability safety coefficient is less than the preset gushing stability threshold, it is determined that the ship lock foundation pit engineering does not meet the gushing stability requirement, the impermeable layer soil body reinforcement construction parameter is determined, and after construction is performed according to the impermeable layer soil body reinforcement construction parameter, the ship lock foundation pit is subjected to permeation inspection. The application solves the technical problem of high cost of the water interception curtain scheme or the deployment of the water pumping well scheme used by the ship lock foundation pit engineering in response to the imbalance of the confined water in the related art.

Description

Technical Field

[0001] This invention relates to the field of lock engineering technology or other related fields, specifically to a method and device for controlling confined water in lock foundation pits based on soil shear strength. Background Technology

[0002] In waterway engineering, the excavation depth of foundation pits often exceeds 20 meters, requiring the passage through multiple strata and approaching or penetrating confined aquifers. Confined water has high hydrostatic pressure due to the constraint of the overlying impermeable layer (or overlying water-impermeable layer). Once its water head pressure exceeds the self-weight and resistance of the impermeable layer at the bottom of the pit, it is prone to instability disasters such as sudden surges, quicksand, and pit bottom heave, which seriously threaten construction safety and the stability of surrounding buildings and structures.

[0003] In related technologies, the pressure balance method specified in the "Technical Specification for Foundation Pit Support" (JGJ 120-2012) is mainly used for the stability calculation of sudden inrush. The core criterion is: considering only the mechanical balance between the self-weight of the impermeable layer at the bottom of the pit and the pressure of the confined water, the corresponding treatment is to deploy a water-stop curtain to cut off the hydraulic connection, or to set up a deep well dewatering system around the foundation pit to actively reduce the confined water head to below the safe threshold. However, these two treatment methods have obvious drawbacks: reducing the pressure of the confined water by installing water-stop curtains and setting up pumping wells is costly and has poor economic efficiency. At the same time, when the water-stop curtain is located on a soil slope, it is prone to cracking due to slope deformation, thus losing its seepage prevention function.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This invention provides a method and apparatus for controlling confined water in a lock foundation pit based on the shear strength of soil, which at least solves the technical problem of high cost associated with the use of water-cutting curtain schemes or pumping well schemes in lock foundation pit engineering when dealing with confined water imbalance in related technologies.

[0006] According to one aspect of the present invention, a method for controlling confined water in a lock pit based on soil shear strength is provided, comprising: calculating the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on geological survey data and the elevation of the bottom surface of the pit excavation; calculating the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable layer soil obtained in advance; calculating a modified inrush stability safety factor based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint coefficient of the local deep pit, the soil shear strength, and the confined water head; determining that the target lock pit project does not meet the inrush stability requirements when the modified inrush stability safety factor is less than a preset inrush stability threshold, and determining the impermeable layer soil reinforcement construction parameters based on the target pit combined intervention path; after construction according to the impermeable layer soil reinforcement construction parameters, performing a seepage inspection on the lock pit, and determining that the stability of the target lock pit project meets the requirements when the inspection results indicate that the wall seepage prevention requirements are met.

[0007] Optionally, the steps of calculating the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on geological survey data and the elevation of the excavation bottom surface of the foundation pit include: determining multiple soil layer types distributed from top to bottom based on the geological survey data, and determining the soil permeability coefficient corresponding to each soil layer type using a pumping test strategy; determining the elevation parameters reached by the confined water pressure and the elevation of the confined water top plate using a confined water test strategy; calculating the confined water head based on the elevation parameters reached by the confined water pressure and the elevation of the confined water top plate; obtaining the excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project; calculating the thickness of the overlying impermeable layer based on the excavation bottom elevation and the elevation of the confined water top plate; and calculating the initial inrush safety factor based on the impermeable layer thickness, the soil unit weight parameters, the elevation parameters reached by the confined water pressure, the excavation bottom elevation, and the impermeable layer thickness.

[0008] Optionally, the step of calculating the shear strength of the soil based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance includes: determining the effective internal friction angle of the cohesive soil in the overlying impermeable layer through a direct shear test or a triaxial consolidated undrained test, and calculating the at-rest earth pressure coefficient based on the effective internal friction angle; or, retrieving a Poisson's ratio reference table for soil types to obtain the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculating the at-rest earth pressure coefficient based on the Poisson's ratio parameter; and calculating the shear strength of the soil based on the cohesion, internal friction angle, initial inrush safety factor, soil unit weight parameter, and at-rest earth pressure coefficient of the overlying impermeable soil layer.

[0009] Optionally, after calculating the shear strength of the soil based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance, the method further includes: obtaining the perimeter and area of ​​the local deep pit of the foundation pit, and calculating the geometric constraint coefficient of the local deep pit of the foundation pit; calculating the resistance parameters of the overlying impermeable soil layer based on the geometric constraint coefficient of the local deep pit of the foundation pit, wherein the resistance parameters of the overlying impermeable soil layer are used to calculate the corrected heave stability safety factor.

[0010] Optionally, before determining the impermeable soil reinforcement construction parameters based on the target foundation pit combined intervention path, the method further includes: dividing the overall foundation pit in the target lock foundation pit project into multiple sub-foundations; calculating the independent perimeter and area of ​​each sub-foundation pit, and calculating the geometric constraint coefficient of the sub-foundation pit; sorting all the geometric constraint coefficients of the sub-foundations, and selecting a predetermined number of sub-foundations in ascending order; calculating the modified surge stability safety factor of each selected sub-foundation pit based on the geometric constraint coefficient, soil unit weight parameter, water unit weight parameter, and soil shear strength; determining that the target lock foundation pit project meets the surge stability requirements if the modified surge stability safety factor of the sub-foundation pit is greater than the preset surge stability threshold; and determining that the target lock foundation pit project does not meet the surge stability requirements if the modified surge stability safety factor of the sub-foundation pit is less than or equal to the preset surge stability threshold, adjusting the number, size, and excavation sequence of the sub-foundations to ensure effective lateral soil constraint between adjacent sub-foundations.

[0011] Optionally, the step of determining the construction parameters for impermeable soil reinforcement based on the target foundation pit combined intervention path includes: when the target foundation pit combined intervention path is selected as high-pressure jet grouting cement sealing process, determining the parameters of the construction jet grouting pipe, grout parameters, and cohesion of the consolidated body to obtain the first reinforcement construction parameters; configuring the grout water-cement ratio parameters, soil moisture content parameters, and curing age to obtain the second reinforcement construction parameters; configuring the grouting volume of different construction jet grouting pipes; and determining the reinforcement construction parameters for the impermeable soil based on the first reinforcement construction parameters, the second reinforcement construction parameters, and the grouting volume of the different construction jet grouting pipes.

[0012] Optionally, after construction according to the impermeable soil reinforcement construction parameters, the step of conducting a permeability inspection of the lock foundation pit includes: conducting a permeability inspection of the lock foundation pit through an in-situ permeability test strategy and a seepage flow data monitoring strategy. The in-situ permeability test strategy includes: excavating a cofferdam at the anti-seepage wall or the junction of the anti-seepage wall and the soil in the target lock foundation pit project. The depth of the cofferdam penetrates the anti-seepage wall into the impermeable layer. Water is injected into the cofferdam to maintain a stable water head height. The amount of water replenished per unit time is recorded, and the permeability coefficient of the anti-seepage wall is calculated.

[0013] According to another aspect of the present invention, a device for controlling confined water in a lock pit based on soil shear strength is also provided, comprising: a pit parameter calculation unit, used to calculate the confined water head, the thickness of the overlying impermeable layer, and the initial heave safety factor based on geological survey data and the elevation of the bottom surface of the pit excavation; a soil shear strength calculation unit, used to calculate the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable layer soil obtained in advance; and a stability safety factor calculation unit, used to calculate the shear strength of the soil based on the thickness of the overlying impermeable layer, the initial heave safety factor, the geometric constraint coefficient of the local deep pit, and the... The soil shear strength and the confined water head are used to calculate the corrected inrush stability safety factor; the reinforcement construction parameter determination unit is used to determine that the target lock foundation pit project does not meet the inrush stability requirements when the corrected inrush stability safety factor is less than the preset inrush stability threshold, and to determine the impermeable soil reinforcement construction parameters based on the target foundation pit combined intervention path; the seepage prevention inspection unit is used to conduct a seepage inspection on the lock foundation pit after construction according to the impermeable soil reinforcement construction parameters, and to determine that the stability of the target lock foundation pit project meets the requirements when the inspection results indicate that the wall seepage prevention requirements are met.

[0014] Optionally, the foundation pit parameter calculation unit includes: a soil layer type determination module, used to determine multiple soil layer types distributed from top to bottom based on the geological survey data, and to determine the soil permeability coefficient corresponding to each soil layer type using a pumping test strategy; a confined water top elevation determination module, used to determine the elevation parameters reached by the confined water pressure and the confined water top elevation using a confined water test strategy; and a confined water head calculation module, used to calculate the required parameters based on the elevation parameters reached by the confined water pressure and the confined water top elevation. The system includes: a confined water head; acquisition of the excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project; an impermeable layer thickness calculation module, used to calculate the thickness of the overlying impermeable layer based on the excavation bottom elevation and the confined water top elevation; and an initial surge safety factor calculation module, used to calculate the initial surge safety factor based on the impermeable layer thickness, the soil unit weight parameters, the elevation parameters reached by the confined water pressure, the excavation bottom elevation, and the impermeable layer thickness.

[0015] Optionally, the soil shear strength calculation unit includes: a static earth pressure coefficient calculation module, used to determine the effective internal friction angle of the cohesive soil in the overlying impermeable layer through a direct shear test or a triaxial consolidated undrained test, and calculate the static earth pressure coefficient based on the effective internal friction angle; or, to retrieve a Poisson's ratio reference table for soil types, obtain the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculate the static earth pressure coefficient based on the Poisson's ratio parameter; and a soil shear strength calculation module, used to calculate the soil shear strength based on the cohesion, internal friction angle, initial inrush safety factor, soil unit weight parameter, and static earth pressure coefficient of the overlying impermeable layer soil.

[0016] Optionally, the lock pit confined water control device based on soil shear strength further includes: a geometric constraint coefficient calculation module, used to calculate the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable soil layer, and then obtain the perimeter and area of ​​the local deep pit of the foundation pit, and calculate the geometric constraint coefficient of the local deep pit of the foundation pit; and a soil resistance parameter calculation unit, used to calculate the resistance parameters of the overlying impermeable soil layer based on the geometric constraint coefficient of the local deep pit of the foundation pit, wherein the resistance parameters of the overlying impermeable soil layer are used to calculate the corrected heave stability safety factor.

[0017] Optionally, the lock pit confined water control device based on soil shear strength further includes: a pit segmentation module, used to segment the overall pit of the target lock pit project into multiple sub-pits before determining the impermeable soil reinforcement construction parameters based on the target pit combined intervention path; a sub-pit constraint coefficient calculation module, used to calculate the independent perimeter and area of ​​each sub-pit and calculate the geometric constraint coefficient of the sub-pit; a sub-pit selection module, used to sort the geometric constraint coefficients of all the sub-pits and select a predetermined number of sub-pits in ascending order; and a sub-pit corrected heave stability safety factor calculation module. The system is used to calculate the modified inrush stability safety factor of each selected sub-foundation pit based on the geometric constraint coefficient, soil unit weight parameter, water unit weight parameter, and soil shear strength. The judgment module is used to determine if the modified inrush stability safety factor of the sub-foundation pit meets the inrush stability requirements when it is greater than a preset inrush stability threshold; and to determine if the modified inrush stability safety factor of the sub-foundation pit does not meet the inrush stability requirements when it is less than or equal to the preset inrush stability threshold, and to adjust the number, size, and excavation sequence of the sub-foundation pits to ensure effective lateral soil constraint between adjacent sub-foundation pits.

[0018] Optionally, the reinforcement construction parameter determination unit includes: a first construction parameter determination module, used to determine the parameters of the jet grouting pipe, grout parameters, and cohesion of the consolidated body when the target foundation pit combination intervention path is selected as high-pressure jet grouting cement sealing process, to obtain the first reinforcement construction parameters; a second construction parameter determination module, used to configure the grout water-cement ratio parameters, soil moisture content parameters, and curing age, to obtain the second reinforcement construction parameters; a grouting volume configuration module, used to configure the grouting volume of different jet grouting pipes; and a soil reinforcement construction parameter determination module, used to determine the reinforcement construction parameters of the impermeable layer soil based on the first reinforcement construction parameters, the second reinforcement construction parameters, and the grouting volume of the different jet grouting pipes.

[0019] Optionally, the seepage prevention inspection unit includes: a seepage prevention inspection module, used to conduct seepage inspection on the lock foundation pit through an in-situ seepage test strategy and a seepage flow data monitoring strategy. The in-situ seepage test strategy includes: excavating a cofferdam at the seepage prevention wall or the junction of the seepage prevention wall and the soil in the target lock foundation pit project. The depth of the cofferdam penetrates the seepage prevention wall into the impermeable layer. Water is injected into the cofferdam to maintain a stable water head height. The amount of water replenished per unit time is recorded, and the permeability coefficient of the seepage prevention wall is calculated.

[0020] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute any of the above-mentioned methods for controlling confined water in a lock pit based on soil shear strength.

[0021] According to another aspect of the present invention, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the above-described method for controlling confined water in a lock pit based on soil shear strength.

[0022] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps of the above-described method for controlling confined water in a lock pit based on soil shear strength.

[0023] In this disclosure, the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor are calculated based on geological survey data and the elevation of the excavated bottom surface of the foundation pit. The shear strength of the soil is calculated based on the pre-obtained cohesion and internal friction angle of the overlying impermeable layer. A modified inrush stability safety factor is calculated based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint coefficient of the local deep pit, the soil shear strength, and the confined water head. If the modified inrush stability safety factor is less than the preset inrush stability threshold, it is determined that the target lock foundation pit project does not meet the inrush stability requirements. Based on the target foundation pit combined intervention path, the impermeable layer soil reinforcement construction parameters are determined. After construction according to the impermeable layer soil reinforcement construction parameters, a seepage inspection is conducted on the lock foundation pit. If the inspection results indicate that the wall seepage prevention requirements are met, it is determined that the stability of the target lock foundation pit project meets the requirements.

[0024] In this disclosure, the confined water head and the thickness of the overlying impermeable layer can be calculated based on geological survey data. The initial inrush safety factor and the lateral shear strength of the impermeable layer soil can then be calculated. Combined with the geometric constraint coefficient of the local deep pit, a modified inrush stability safety factor is obtained. When the requirements are met, it indicates that the soil's shear strength is sufficient to resist the confined water, eliminating the need for any interception or dewatering works and directly saving on curtain wall construction costs and long-term pumping operation and maintenance costs. However, when the requirements are not met, this embodiment does not use a full-section curtain wall. Instead, it implements precise reinforcement for local high-risk areas. Based on the target foundation pit combined intervention path, the construction parameters for impermeable layer soil reinforcement are determined to improve local cohesion, rather than full closure. This significantly reduces cement usage and the number of boreholes, avoiding ineffective construction. Thus, without increasing material input, the cohesion of the impermeable layer soil is improved, greatly reducing project costs. This solves the technical problem of high costs associated with interception curtain schemes or pumping well schemes used in ship lock foundation pit engineering when dealing with confined water imbalance. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1 This is a flowchart of an optional method for controlling confined water in a lock pit based on soil shear strength, according to an embodiment of the present invention.

[0027] Figure 2 This is an optional cross-sectional view of the foundation pit excavation according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of an optional inrush stability analysis model according to an embodiment of the present invention when the bottom waterproof layer is not reinforced;

[0029] Figure 4 This is a schematic diagram of an optional sectional excavation of the foundation pit according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of an optional impermeable layer reinforcement treatment according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of an optional confined water control device for a lock pit based on soil shear strength according to an embodiment of the present invention;

[0032] Figure 7 This is a hardware structure block diagram of an electronic device (or mobile device) that performs a method for controlling confined water in a lock pit based on soil shear strength, according to an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] To facilitate understanding of the present invention by those skilled in the art, some terms or nouns involved in the various embodiments of the present invention are explained below:

[0036] The coefficient of earth pressure at rest represents the ratio of the effective horizontal stress to the effective vertical stress in soil under conditions of no lateral strain. It is used to calculate the effective stress component in the lateral resistance of soil and affects the calculation results of soil shear strength.

[0037] The confined water head refers to the height difference between the piezometer water level in a confined aquifer and a certain reference surface, representing the magnitude of the hydrostatic pressure exerted by the confined water on the impermeable layer at the bottom of the pit.

[0038] An impermeable layer / waterproof layer, also known as an aquitard, refers to a soil layer with an extremely low permeability coefficient that can effectively block the seepage of groundwater, such as silty clay. The thickness of the impermeable layer directly affects the ability to balance the pressure of confined water.

[0039] The surge stability safety factor, denoted as K1 or K2 in this invention, is used to quantify the ability of the foundation pit bottom slab to resist the failure of confined water surge. K1 is the traditional safety factor that only considers the weight of the soil, while K2 is the modified safety factor that incorporates the lateral resistance of the soil.

[0040] High-pressure jet grouting is a reinforcement process that uses high-pressure cement slurry jets to cut, mix, and replace in-situ soil to form a cylindrical cement-soil consolidation body. It can improve soil cohesion and is used to locally reinforce waterproof layers to enhance shear strength.

[0041] Cement soil mixing pile (CSMP) is a composite soil pile formed by mechanically mixing cement slurry or powder with the in-situ soil to create a composite soil pile with certain strength and low permeability.

[0042] Water-cement ratio, or W / C for short, refers to the mass ratio of water to cement in cement slurry and is a key process parameter that affects the strength of cement-soil consolidation.

[0043] High-pressure jet grouting (HPJG) uses high-pressure grout to impact, cut, and mix with the soil to form a cement-soil consolidation, improving soil cohesion and impermeability. It is suitable for local reinforcement of deep, impermeable layers.

[0044] The re-spraying process refers to multiple spraying operations on the same injection hole to improve the uniformity and continuity of the cement-soil consolidation. It is suitable for areas with well-developed soil fissures or high reinforcement requirements.

[0045] It should be noted that the method and apparatus for controlling confined water in lock pits based on soil shear strength disclosed herein can be used in the field of lock pit technology when controlling confined water in lock pits based on soil shear strength, and can also be used in any field other than lock pit technology when controlling confined water in lock pits based on soil shear strength. This disclosure does not limit the application field of the method and apparatus for controlling confined water in lock pits based on soil shear strength.

[0046] It should be noted that in this disclosure, customer information is collected and analyzed, and users are provided with corresponding operation entry points to choose whether to agree to or reject the automated decision results; if the user chooses to reject, the process will proceed to the expert decision-making process.

[0047] The following embodiments of the present invention can be applied to various systems / applications / equipment for controlling confined water in lock pits based on soil shear strength. The present invention is applicable to deep foundation pit support, lock pit engineering, and underground engineering construction scenarios, especially to water transport infrastructure projects near rivers, lakes, and seas, including lock pits, wharf berth pits, channel lock chambers, and port breakwater foundations. In these scenarios, the excavation depth of the pits is generally deep (e.g., exceeding 15 meters), the underlying confined aquifer is thick, the water head pressure is high, the impermeable layer is thin, and the geological conditions are complex. Traditional cutoff curtain construction is difficult and the dewatering system has high operating costs.

[0048] This invention incorporates soil shear strength into the inrush stability calculation system, correcting the traditional conservative assessment method that relies solely on gravity balance, and achieving a more refined assessment of confined water risk. When the shear strength of the impermeable layer is insufficient, lateral restraint can be enhanced by optimizing the excavation zoning layout, or the impermeable layer can be locally reinforced using techniques such as high-pressure jet grouting and cement mixing piles. This allows for meeting the inrush safety factor requirements without requiring a full-section cutoff wall or large-scale deep well dewatering. It also reduces the impact of a significant drop in groundwater level on the surrounding environment, improving the economy, adaptability, and environmental friendliness of the construction plan.

[0049] The present invention will now be described in detail with reference to various embodiments.

[0050] Example 1

[0051] According to an embodiment of the present invention, an embodiment of a method for controlling confined water in a lock pit based on soil shear strength is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0052] Figure 1 This is a flowchart of an optional method for controlling confined water in a lock pit based on soil shear strength, according to an embodiment of the present invention. Figure 1 As shown, the method includes the following steps S101 to S102. The present invention will be described in detail below with reference to each implementation step.

[0053] Step S101: Calculate the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on the geological survey data and the elevation of the bottom surface of the excavation pit.

[0054] Optionally, step S101 includes: determining multiple soil layer types distributed from top to bottom based on geological survey data, and determining the soil permeability coefficient corresponding to each soil layer type using a pumping test strategy; determining the elevation parameters reached by the confined water pressure and the elevation of the confined water top plate using a confined water test strategy; calculating the confined water head based on the elevation parameters reached by the confined water pressure and the elevation of the confined water top plate; obtaining the excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project; calculating the thickness of the overlying impermeable layer based on the excavation bottom elevation and the elevation of the confined water top plate; and calculating the initial inrush safety factor based on the impermeable layer thickness, soil unit weight parameters, the elevation parameters reached by the confined water pressure, the excavation bottom elevation, and the impermeable layer thickness.

[0055] In this embodiment, the soil layers, distributed from top to bottom, may include silty clay, fine sand, and other soil layers. Using a pumping test strategy to determine the permeability coefficient of each soil layer type helps to clarify the seepage characteristics of each layer, providing a basis for determining the boundary between confined aquifers and impermeable layers, thereby identifying the occurrence environment and flow path of confined water. The pumping test strategy obtains the measured values ​​of the permeability coefficient of each layer by setting up observation wells in different soil layers and recording the water level recovery curves. Furthermore, using a confined water test strategy to determine the elevation parameters reached by the confined water pressure and the elevation of the confined water top plate can accurately obtain the hydrostatic pressure distribution characteristics of the confined water under natural conditions. The confined water pressure elevation reflects the water level in the piezometer at the top of the aquifer, and the confined water top plate elevation is the elevation of the bottom interface of the impermeable layer.

[0056] In this embodiment, further obtaining the excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project helps to construct a mechanical equilibrium model of the soil and water body after the foundation pit excavation. The excavation bottom elevation is used to determine the remaining thickness of the impermeable layer after its weakening; the soil unit weight parameters are used to calculate the self-weight of the overlying soil layer; and the water unit weight parameters serve as a standard reference value for converting the water head into pressure per unit area. Then, based on the excavation bottom elevation and the elevation of the confined water top plate, the thickness of the overlying impermeable layer is calculated. This is the geometric basis for determining the impermeable layer's ability to resist confined water, and the thickness of this overlying impermeable layer determines the soil's ability to balance the pressure of the confined water.

[0057] Step S102: Calculate the shear strength of the soil based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance.

[0058] Optionally, the step of calculating the shear strength of the soil based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance includes: determining the effective internal friction angle of the cohesive soil in the overlying impermeable layer through a direct shear test or a triaxial consolidated undrained test, and calculating the at-rest earth pressure coefficient based on the effective internal friction angle; or, retrieving the Poisson's ratio reference table for soil types, obtaining the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculating the at-rest earth pressure coefficient based on the Poisson's ratio parameter; and calculating the shear strength of the soil based on the cohesion, internal friction angle, initial inrush safety factor, soil unit weight parameter, and at-rest earth pressure coefficient of the overlying impermeable soil layer.

[0059] In this embodiment, the effective internal friction angle of the cohesive soil in the overlying impermeable layer can be determined by direct shear test or triaxial consolidated undrained test, and the at-rest earth pressure coefficient can be calculated based on the effective internal friction angle. This helps to obtain the shear mechanical parameters of the soil under the actual stress path. This method directly reflects the evolution characteristics of the lateral stress state of the soil under the action of confined water, and provides a measured basis for determining the at-rest earth pressure coefficient. In another optional embodiment, the present invention retrieves the Poisson's ratio reference table for soil types to obtain the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculates the at-rest earth pressure coefficient based on the Poisson's ratio parameter. This can provide a reasonable engineering alternative when in-situ test data is lacking. Based on the Poisson's ratio range corresponding to different soil states (such as plastic and soft plastic), the at-rest earth pressure coefficient applicable to this embodiment can be derived.

[0060] Subsequently, the shear strength of the soil can be calculated based on the cohesion, internal friction angle, initial heave safety factor, soil unit weight parameters, and static earth pressure coefficient of the overlying impermeable soil layer. This process combines the soil's cohesion and frictional resistance with the lateral effective stress to comprehensively express the shear strength, making it no longer an empirical judgment but a quantitative indicator based on physical mechanisms.

[0061] Optionally, after calculating the shear strength of the soil based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance, the method further includes: obtaining the perimeter and area of ​​the local deep pit of the foundation pit, and calculating the geometric constraint coefficient of the local deep pit of the foundation pit; calculating the resistance parameters of the overlying impermeable soil layer based on the geometric constraint coefficient of the local deep pit of the foundation pit, wherein the resistance parameters of the overlying impermeable soil layer are used to calculate the corrected heave stability safety factor.

[0062] In this embodiment, the geometric constraint coefficient of the local deep pit can be calculated by obtaining the perimeter and area of ​​the pit. This helps to quantify the lateral constraint capacity of the soil surrounding the impermeable layer at the bottom of the pit on the shear failure surface. For example, the geometric constraint coefficient can be expressed as α=D. The equation is expressed in l / S form, where the perimeter l reflects the boundary length, the area S reflects the stress area, and the ratio of perimeter l to area S reflects the synergistic shear resistance effect of the soil in the horizontal direction. D is the thickness of the impermeable layer. Furthermore, calculating the resistance parameters of the overlying impermeable soil layer based on the geometric constraint coefficient of the local deep pit involves transforming the shear strength τ of the soil per unit area into the total resistance N1 = α·τ acting on the entire area at the bottom of the pit. This parameter breaks through the traditional equilibrium model that only considers the vertical weight of the soil, introducing the contribution of lateral shear resistance to the inrush stability, thus extending the resistance model from one-dimensional vertical equilibrium to a two-dimensional shear-weight coupling system. The resistance parameters of the overlying impermeable soil layer are used to calculate the corrected inrush stability safety factor, which helps to superimpose the additional stability margin provided by the lateral shear mechanism of the soil on the original initial safety factor based on soil weight, allowing the safety factor calculation to transition from a conservative simplified model to a mechanical model that more closely reflects the actual stress distribution.

[0063] Step S103: Calculate the corrected inrush stability safety factor based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint factor of the local deep pit, the soil shear strength, and the confined water head.

[0064] Step S103 expands the traditional balance relationship between soil self-weight and buoyancy force of confined water into a comprehensive stability assessment model that includes lateral shear resistance contribution. This calculation process obtains the soil resistance component by multiplying the geometric constraint coefficient by the soil shear strength and superimposing it into the initial surge safety factor, so that the assessment result reflects the true stress state of the pit bottom aquitard under shear failure mode.

[0065] Optionally, before determining the impermeable soil reinforcement construction parameters based on the target foundation pit combined intervention path, the method further includes: dividing the overall foundation pit in the target lock foundation pit project into multiple sub-foundations; calculating the independent perimeter and area of ​​each sub-foundation pit, and calculating the geometric constraint coefficient of the sub-foundation pit; sorting all the geometric constraint coefficients of the sub-foundations pits, and selecting a predetermined number of sub-foundations pits in ascending order; calculating the modified surge stability safety factor of the sub-foundation pit based on the geometric constraint coefficient, soil unit weight parameter, water unit weight parameter, and soil shear strength of each selected sub-foundation pit; determining that the target lock foundation pit project meets the surge stability requirements if the modified surge stability safety factor of the sub-foundation pit is greater than the preset surge stability threshold; and determining that the target lock foundation pit project does not meet the surge stability requirements if the modified surge stability safety factor of the sub-foundation pit is less than or equal to the preset surge stability threshold, adjusting the number, size, and excavation sequence of the sub-foundations pits to ensure that effective lateral soil constraints are formed between adjacent sub-foundations pits.

[0066] This embodiment divides the overall foundation pit of the target lock project into multiple sub-pits, which helps to decompose the unified risk of large-scale excavation into independent stability problems in multiple local areas. By dividing the construction units, the unexcavated areas become natural lateral constraints, thereby forming a passive earth pressure support system during excavation and providing additional shear boundary conditions for local areas. Subsequently, for each sub-pit, the independent perimeter and area can be calculated, and the geometric constraint coefficient of the sub-pit can be calculated. This helps to quantify the lateral constraint capacity of excavation units with different shapes and sizes. The value of the geometric constraint coefficient increases as the pit shape tends to be narrower, enabling the evaluation results to respond to the influence of different cross-sectional shapes on stability and improving the spatial adaptability of the model.

[0067] Sort the geometric constraint coefficients of all sub-pits and select a predetermined number of sub-pits in ascending order. This helps to identify the most unfavorable working conditions first, and select sub-pits with smaller α values ​​for verification because they have the lowest lateral shear contribution. If this type of area meets the stability requirements, the remaining areas have a higher safety margin, thus achieving coverage of the largest risk range with minimal computational cost. Then, calculate the modified inrush stability safety factor of the sub-pits. The refined calculation process that couples local geometric features with soil mechanical parameters makes the stability judgment no longer rely on the average assumption of the entire pit, but on the independent stress state of each sub-unit, improving the matching degree between the assessment results and the actual excavation behavior. When the modified inrush stability safety factor of the sub-pit is greater than the preset inrush stability threshold, it is determined that the target lock pit project meets the inrush stability requirements. This indicates that the lateral soil constraint system formed by the zonal excavation can effectively resist the backwater effect of the confined water, and there is no need to implement high-cost measures such as cutoff walls or pumping wells.

[0068] Furthermore, in this embodiment, when it is determined that the target lock foundation pit project does not meet the requirements for sudden surge stability, the number, size, and excavation sequence of the sub-foundations can be adjusted to ensure that effective lateral soil constraints are formed between adjacent sub-foundations. This can be achieved by increasing the number of sub-foundations to reduce the individual excavation area, optimizing the excavation sequence to create a "soil arch" or "wall" effect between adjacent unexcavated areas, or adjusting the foundation pit boundary shape to increase the ratio of perimeter to area, thereby improving the geometric constraint coefficient and realizing active control of stability and dynamic optimization of the construction path.

[0069] Step S104: If the corrected surge stability safety factor is less than the preset surge stability threshold, it is determined that the target lock foundation pit project does not meet the surge stability requirements. Based on the target foundation pit combined intervention path, the construction parameters for the impermeable soil reinforcement are determined.

[0070] When it is determined that the target lock foundation pit project does not meet the requirements for sudden surge stability, the construction parameters for the reinforcement of the impermeable soil layer can be determined based on the combined intervention path of the target foundation pit. This involves targeted reinforcement measures taken to address the insufficient shear capacity in localized areas. By actively improving the cohesion and integrity of the impermeable soil layer, the soil that originally could not meet the stability requirements acquires the mechanical ability to resist the backwater pressure, achieving a shift from passive water control to actively enhancing the soil's bearing capacity. Optionally, the steps for determining the construction parameters for the reinforcement of the impermeable soil layer based on the combined intervention path of the target foundation pit include: when the combined intervention path of the target foundation pit is selected as high-pressure jet grouting cement sealing technology, determining the parameters of the jet grouting pipe, the grout parameters, and the cohesion of the consolidated body to obtain the first reinforcement construction parameters; configuring the grout water-cement ratio parameters, soil moisture content parameters, and curing age to obtain the second reinforcement construction parameters; configuring the grouting volume for different jet grouting pipes; and determining the reinforcement construction parameters for the impermeable soil layer based on the first reinforcement construction parameters, the second reinforcement construction parameters, and the grouting volume for different jet grouting pipes.

[0071] In this embodiment, a single-pipe, double-pipe, or triple-pipe jet grouting system can be selected according to different soil conditions. The nozzle diameter, lifting speed, and rotation frequency can be matched to ensure that the cement slurry is fully mixed with the soil, forming a cement-soil consolidation body with the target cohesion (e.g., 40–150 kPa), thereby improving the intrinsic shear strength of the waterproof layer. Then, the water-cement ratio of the slurry, the moisture content of the soil, and the curing age are configured to obtain the second reinforcement construction parameters, which help to control the diffusion range and solidification efficiency of the cement slurry. When the water-cement ratio is controlled in the range of 0.8–1.0, the viscosity of the slurry is moderate, which can enhance the bonding density with saturated silty clay and increase the cohesion of the consolidation body by 20%–40%. When the soil moisture content is saturated, the slurry penetration is more uniform, and the structure of the consolidation body is more continuous. Furthermore, a curing period of 28 days can increase the cohesion by 1.5–2.0 times compared to 7 days, ensuring that the reinforced body reaches the design strength before excavation.

[0072] Furthermore, this embodiment configures different grouting volumes for different construction jet grouting pipes, which helps to adjust the grouting volume per unit length according to the differences in soil permeability. For example, when the diameter of a single-pipe jet grouting pile is 0.6 to 0.8 m, the grouting volume is 0.15 to 0.30 m³ / m, which is suitable for conventional cohesive soil layers. When the diameter of a double-pipe or triple-pipe system is increased to 0.8 to 1.2 m, the grouting volume can be increased to 0.30 to 0.60 m³ / m. For areas with developed fissures or high permeability, it can be increased to 0.60 to 0.90 m³ / m, and combined with the re-jetting process, the continuity of the consolidated body is enhanced.

[0073] Step S105: After construction is carried out according to the construction parameters for the impermeable soil layer reinforcement, a seepage inspection is conducted on the lock foundation pit. If the inspection results indicate that the wall seepage prevention requirements are met, it is determined that the stability of the target lock foundation pit project meets the requirements.

[0074] If the inspection results indicate that the wall's seepage prevention requirements are met, confirming that the stability of the target lock foundation pit project meets the requirements is a closed-loop control link for verifying the continuity, density, and seepage resistance of the reinforced body. The actual seepage response is used to verify whether the improvement in soil shear strength has successfully translated into water-stopping performance. Optionally, after construction according to the impermeable soil reinforcement construction parameters, the steps for conducting a seepage inspection of the lock foundation pit include: conducting a seepage inspection of the lock foundation pit using in-situ seepage testing strategies and seepage flow data monitoring strategies. The in-situ seepage testing strategy includes: excavating a cofferdam at the seepage prevention wall or the junction of the seepage prevention wall and the soil in the target lock foundation pit project. The cofferdam depth penetrates the seepage prevention wall into the impermeable layer. Water is injected into the cofferdam, maintaining a stable water head height, recording the water replenishment volume per unit time, and calculating the permeability coefficient of the seepage prevention wall.

[0075] The in-situ permeability test strategy requires excavating a cofferdam and recording the amount of water replenished per unit time. This simulates the actual seepage path of confined water in the reinforced body. By quantitatively determining the relationship between the amount of water replenished per unit time and the head difference, the measured permeability coefficient of the wall is obtained, which helps to determine whether the cement-soil consolidation body forms a continuous, dense, low-permeability barrier. It should be noted that the cofferdam excavation depth needs to penetrate the impermeable wall and enter the predetermined range of the underlying impermeable layer (e.g., 0.5–1.0 m). This helps to eliminate the interference of the underlying aquifer on the test results, ensuring that the measured seepage only reflects the impermeability of the reinforced wall itself. In addition, this embodiment uses well wall support, which can prevent measurement distortion caused by borehole collapse and maintain the stability of the hydraulic boundary conditions.

[0076] Through the above steps, the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor can be calculated based on geological survey data and the elevation of the excavation bottom of the foundation pit. Based on the pre-obtained cohesion and internal friction angle of the overlying impermeable soil, the shear strength of the soil is calculated. Based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint coefficient of the local deep pit, the shear strength of the soil, and the confined water head, a modified inrush stability safety factor is calculated. If the modified inrush stability safety factor is less than the preset inrush stability threshold, it is determined that the target lock foundation pit project does not meet the inrush stability requirements. Based on the target foundation pit combined intervention path, the impermeable soil reinforcement construction parameters are determined. After construction according to the impermeable soil reinforcement construction parameters, a seepage inspection is conducted on the lock foundation pit. If the inspection results indicate that the wall seepage prevention requirements are met, it is determined that the stability of the target lock foundation pit project meets the requirements. In this embodiment, the confined water head and the thickness of the overlying impermeable layer can be calculated based on geological survey data. The initial inrush safety factor and the lateral shear strength of the impermeable layer soil can then be calculated. Combined with the geometric constraint coefficient of the local deep pit, a modified inrush stability safety factor is obtained. When the requirements are met, it indicates that the soil's shear strength is sufficient to resist the confined water, eliminating the need for any interception or dewatering works and directly saving on curtain wall construction costs and long-term pumping operation and maintenance costs. However, when the requirements are not met, this embodiment does not use a full-section curtain wall. Instead, it implements precise reinforcement for local high-risk areas. Based on the target foundation pit combined intervention path, the impermeable layer soil reinforcement construction parameters are determined to improve local cohesion, rather than full closure. This significantly reduces cement usage and the number of boreholes, avoiding ineffective construction. Thus, without increasing material input, the cohesion of the impermeable layer soil is improved, greatly reducing project costs. This solves the technical problem of high costs associated with interception curtain schemes or pumping well schemes used in ship lock foundation pit engineering when dealing with confined water imbalance.

[0077] The following describes in detail another optional implementation method.

[0078] This invention proposes a method for controlling confined water in foundation pits based on soil shear strength. Taking the Weishan Third-Line Ship Lock foundation pit project as an example, the control method includes the following steps:

[0079] Step 1: Analyze the permeability characteristics of the soil and rock layers, determine the elevation of the confined water top plate, and calculate the confined water head.

[0080] According to the geological survey report, the soil layers distributed from top to bottom include silty clay and fine sand. The bottom elevation of the silty clay layer is approximately -10.8m, below which lies the fine sand layer. (See [link to geological survey report]). Figure 2 The permeability coefficient of each soil layer was determined through pumping tests, with the silty clay having a permeability coefficient of 10. -7 The permeability coefficient of the silty sand layer is 10 cm / s, indicating a basically impermeable layer; the permeability coefficient of the fine sand layer is 10. -3The pressure is cm / s, indicating a medium permeability layer. Through a confined water test, the pressure of the confined water was measured to reach an elevation of 3.50m, and the elevation of the top confined water slab was -10.8m. Therefore, the confined water head is approximately 3.5m - (-10.8m) = 14.3m.

[0081] Step 2: Conduct a calculation and analysis of the confined water surge resistance to obtain the safety factor for the stability of the foundation pit surge.

[0082] According to the construction requirements of the Weishan Third-Line Ship Lock foundation pit project, the bottom elevation of the foundation pit excavation is -4.8m. The initial foundation pit heave stability safety factor is calculated according to the predetermined formula. <1.1, does not meet the specification requirements, and a sudden surge will occur. For the thickness of the impermeable layer, This refers to the bulk density of the soil (19.8). This refers to the specific gravity of water (10).

[0083] Step 3: Calculate the shear strength of the overlying impermeable soil layer. .

[0084] Under the action of confined water, the most likely scenario is overall shear failure along the side of the impermeable layer at the bottom of the pit. Figure 3 The diagram shows a stability analysis model for a sudden surge when the impermeable layer at the bottom of the pit is not reinforced. It illustrates the confined aquifer, the impermeable layer, and the original ground elevation. Figure 3 The natural soil portion shown in the image is the overall shear failure surface indicated by two downward arrows.

[0085] According to the geological survey report, the overlying impermeable layer is a silty clay layer with a cohesion of c=55kPa and an internal friction angle of ψ=14.4°.

[0086] The shear strength of the overlying impermeable soil layer 55kPa +0.5 19.8 tan14.4° = 55 + 0.5 19.8 tan14.4° = 59.9 kPa. Wherein, The coefficient of earth pressure at rest. For the cohesion of the overlying impermeable layer, The effective internal friction angle is the overlying impermeable layer.

[0087] It should be noted that the soil in the local deep pit is in an overconsolidated state after unloading. However, the at-rest earth pressure coefficient corresponding to the overconsolidated state is larger than that of the normally consolidated state. Therefore, the at-rest earth pressure coefficient under the normally consolidated state is still used in the calculation process of this embodiment. For normally consolidated cohesive soil that has not been subjected to stress greater than its existing self-weight after remolding or deposition, the formula for calculating the at-rest earth pressure coefficient is: =1-sin In the formula: The effective internal friction angle (°) for cohesive soil needs to be determined through a direct shear test or a triaxial consolidated undrained test (CU). When a direct shear test or a triaxial consolidated undrained test is not performed, the coefficient of earth pressure at rest can be estimated using Poisson's ratio. = = =0.43; the Poisson's ratio for different soil types can be determined according to Table 1 below:

[0088] Table 1 Poisson's ratio for different soil layers

[0089]

[0090] Step 4: Calculate the resistance N1 of the overlying impermeable soil layer and the corrected heave stability safety factor when the soil is unreinforced, based on the geometric characteristics of the foundation pit. .

[0091] First, the soil resistance can be calculated. = .

[0092] A dimensionless coefficient relating to the local deep pit planar dimensions and the thickness D of the impermeable layer. = Let l and S be the perimeter (m) and area (m²) of the local deep pit, respectively. 2 For the ship lock foundation pit of the Weishan Third Line Ship Lock Project, the perimeter of the local deep pit is l=332m and the area is S=1199m². 2 .

[0093] but =1.48>1.1, which meets the surge stability requirements.

[0094] By comparing and correcting the surge stability safety factor Based on the preset surge stability safety threshold of 1.1, it can be seen that the current foundation pit does not need to be reinforced to meet the surge stability requirements.

[0095] Step 5: When the cohesion of the overlying impermeable soil layer is low and cannot meet the requirements for surge stability, there are two treatment methods.

[0096] Assuming an impermeable silty clay layer with a cohesion of c=17kPa and an internal friction angle of ψ=14.4°.

[0097] 17kPa +0.5 19.8 tan14.4° = 14 + 0.5 19.8 tan14.4° = 21.9 kPa

[0098] Soil resistance =

[0099] =1.08<1.1, which does not meet the surge stability requirements.

[0100] The first approach is to change the excavation process, dividing the large foundation pit into smaller pits to increase the beneficial effect of lateral restraint and achieve stability against sudden inrush.

[0101] like Figure 4 As shown, based on construction process requirements, the foundation pit was divided into 11 smaller foundation pits, Q1, Q2...Q11, for excavation. Among them, foundation pits Q1 and Q5... When the value is minimized, the stability of the foundation pit is recalculated:

[0102] For foundation pit Q1, l=44m, S=120m 2 .

[0103] Soil resistance =

[0104] =1.16>1.1, which meets the surge stability requirements.

[0105] For the Q5 foundation pit, the perimeter of the local deep pit is l = 46m, and the area is S = 102m². 2 .

[0106] Soil resistance =

[0107] =1.245>1.1, which meets the surge stability requirements.

[0108] The second treatment method is to reinforce the impermeable soil layer to improve its shear strength (such as cohesion c) and enhance the foundation pit's resistance to sudden inrush.

[0109] For example, injecting cement grout into an impermeable layer can increase the cohesion (c) from 17 kPa to 55 kPa, which can significantly improve the stability and safety factor of the foundation pit against sudden inrush. (See...) Figure 5 The construction process that can be selected is one of the following: high-pressure jet grouting or cement mixing grouting.

[0110] Step 6: Determine process parameters.

[0111] For the high-pressure jet grouting process, the cohesion of the cement-soil consolidation formed by high-pressure jet grouting is significantly improved. In this embodiment of the invention, the process parameters are as follows:

[0112] Construction methods: (1) Conventional single-pipe jet grouting (cement grout): the cohesion of the solidified body can reach 40-100kPa, which is 3-10 times higher than that of natural soil; (2) Double-pipe / triple-pipe jet grouting (with admixtures or improved grout): (3) By cutting the soil through the linkage of gas, liquid and solid three phases, the grout and soil are mixed more evenly, and the cohesion can be increased to 80-150kPa, which is suitable for projects with high reinforcement strength requirements (such as foundation pit water-stop curtain, foundation reinforcement).

[0113] Key influencing factors: (1) Water-cement ratio of grout: a thick grout with a water-cement ratio of 0.8-1.0 can increase the c value of the consolidated body by 20%-40% compared to a thin grout with a water-cement ratio of 1.5-2.0; (2) Soil moisture content: the reinforcement effect of saturated silty clay is better than that of dry soil, the former has more sufficient grout diffusion and a higher increase in c value; (3) Curing age: the c value of the consolidated body at 28 days is about 1.5-2.0 times that at 7 days.

[0114] Grouting volume: (1) Single-pipe jet grouting (pile diameter 0.6-0.8m): grouting volume per meter 0.15-0.30m³; Double-pipe / triple-pipe jet grouting (pile diameter 0.8-1.2m): grouting volume per meter 0.30-0.60m³; Special working conditions (such as soil fissure development, requiring reinforcement): grouting volume can be increased to 0.60-0.90m³ / m, and it is necessary to cooperate with the re-jetting process.

[0115] Step 7: Overall effect inspection and treatment of the high-pressure spray wall.

[0116] The overall seepage prevention effect can be analyzed by observing and comparing the water level difference and seepage volume through a pressure measuring device. Alternatively, the seepage volume can be measured during the excavation of the foundation pit, and any concentrated seepage points can be checked. If seepage points are found, seepage prevention treatment needs to be carried out again.

[0117] Inspection of the seepage prevention effect of high-pressure jet grouting cutoff walls: The core is to verify whether the continuity, integrity, and permeability coefficient of the wall meet the design requirements. Common methods are divided into two main categories: in-situ testing and auxiliary testing. In-situ permeability testing involves excavating circular or square wells on the cutoff wall or at the junction of the wall and the soil. The well depth must penetrate the cutoff wall to the lower impermeable layer by 0.5-1.0m, and the well walls must be properly supported to prevent collapse. Water is injected into the well to maintain a stable water head height (usually 2-3m above the groundwater level), and the amount of water added per unit time is recorded. The permeability coefficient of the wall is then calculated using a formula.

[0118] Through the above implementation methods, this invention, by incorporating soil shear strength into the calculation of foundation pit inrush stability, breaks through the traditional simplified model that relies solely on the balance of soil gravity and confined water pressure. This expands stability assessment from a single vertical force system to a composite mechanical system involving the synergistic effects of vertical pressure and lateral shear. By optimizing the overall excavation of the foundation pit into multiple sub-pit zones, and utilizing the unexcavated soil as a natural lateral constraint, the geometric constraint coefficient of local areas is increased. This quantifies the soil's shear contribution and adds it to the safety factor, achieving effective control of the risk of confined water inrush without the need for additional water-stopping curtains or depressurization wells.

[0119] Through the above-described embodiments, the present invention can use high-pressure jet grouting and other processes to locally reinforce impermeable layers, with the core objective of improving soil cohesion. By combining the systematic matching of parameters such as water-cement ratio, moisture content, curing age and grouting volume, a cement-soil consolidation body with controllable strength and significantly reduced permeability coefficient is formed, enabling the reinforced area to have independent water-blocking capacity and expanding its applicable boundaries in deep confined aquifers or deformed slope areas.

[0120] Through the above-described embodiments, the present invention can achieve structured control of the risk of confined water in foundation pits without relying on traditional cutoff walls and deep well dewatering, thereby reducing the investment in a large number of underground continuous walls, cast-in-place piles and pumping equipment, reducing the disturbance of construction to the surrounding environment, shortening the construction period, and avoiding secondary risks caused by curtain cracking, dewatering failure and other reasons.

[0121] The following is a detailed description with reference to another embodiment.

[0122] Example 2

[0123] The lock pit confined water control device based on soil shear strength provided in this embodiment includes multiple implementation units, each of which corresponds to a specific implementation step in Embodiment 1 above.

[0124] Figure 6 This is a schematic diagram of an optional confined water control device for a lock pit based on soil shear strength, according to an embodiment of the present invention. Figure 6 As shown, the lock pit pressurized water control device based on soil shear strength may include: pit parameter calculation unit 61, soil shear strength calculation unit 62, stability safety factor calculation unit 63, reinforcement construction parameter determination unit 64, and seepage prevention inspection unit 65.

[0125] Among them, the foundation pit parameter calculation unit 61 is used to calculate the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on geological survey data and the elevation of the bottom surface of the foundation pit excavation.

[0126] The soil shear strength calculation unit 62 is used to calculate the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance.

[0127] The stability safety factor calculation unit 63 is used to calculate the corrected inrush stability safety factor based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint factor of the local deep pit, the shear strength of the soil, and the confined water head.

[0128] The reinforcement construction parameter determination unit 64 is used to determine that the target lock foundation pit project does not meet the surge stability requirements when the corrected surge stability safety factor is less than the preset surge stability threshold, and to determine the reinforcement construction parameters of the impermeable soil layer based on the target foundation pit combined intervention path.

[0129] The seepage prevention inspection unit 65 is used to conduct seepage inspection on the lock foundation pit after construction according to the impermeable soil reinforcement construction parameters, and to determine that the stability of the target lock foundation pit project meets the requirements if the inspection results indicate that the seepage prevention requirements of the wall are met.

[0130] The aforementioned confined water control device for lock pits based on soil shear strength can calculate the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor using the pit parameter calculation unit 61 based on geological survey data and the bottom elevation of the pit excavation. It can also calculate the soil shear strength using the soil shear strength calculation unit 62 based on the pre-obtained cohesion and internal friction angle of the overlying impermeable layer. Finally, it can calculate the stability safety factor using the overlying impermeable layer thickness, the initial inrush safety factor, the geometric constraint coefficient of local deep pits, and the soil shear strength. The pressure head is used to calculate and correct the surge stability safety factor. If the corrected surge stability safety factor is less than the preset surge stability threshold, the reinforcement construction parameter determination unit 64 determines that the target lock foundation pit project does not meet the surge stability requirements. Based on the target foundation pit combined intervention path, the impermeable soil reinforcement construction parameters are determined. After the seepage prevention inspection unit 65 carries out the construction according to the impermeable soil reinforcement construction parameters, the lock foundation pit is inspected for seepage. If the inspection results indicate that the wall seepage prevention requirements are met, the stability of the target lock foundation pit project is determined to meet the requirements. In this embodiment, the confined water head and the thickness of the overlying impermeable layer can be calculated based on geological survey data. The initial inrush safety factor and the lateral shear strength of the impermeable layer soil can then be calculated. Combined with the geometric constraint coefficient of the local deep pit, a modified inrush stability safety factor is obtained. When the requirements are met, it indicates that the soil's shear strength is sufficient to resist the confined water, eliminating the need for any interception or dewatering works and directly saving on curtain wall construction costs and long-term pumping operation and maintenance costs. However, when the requirements are not met, this embodiment does not use a full-section curtain wall. Instead, it implements precise reinforcement for local high-risk areas. Based on the target foundation pit combined intervention path, the impermeable layer soil reinforcement construction parameters are determined to improve local cohesion, rather than full closure. This significantly reduces cement usage and the number of boreholes, avoiding ineffective construction. Thus, without increasing material input, the cohesion of the impermeable layer soil is improved, greatly reducing project costs. This solves the technical problem of high costs associated with interception curtain schemes or pumping well schemes used in ship lock foundation pit engineering when dealing with confined water imbalance.

[0131] Optionally, the foundation pit parameter calculation unit includes: a soil layer type determination module, used to determine multiple soil layer types distributed from top to bottom based on geological survey data, and to determine the soil permeability coefficient corresponding to each soil layer type using a pumping test strategy; a confined water top elevation determination module, used to determine the elevation parameters reached by the confined water pressure and the confined water top elevation using a confined water test strategy; a confined water head calculation module, used to calculate the confined water head based on the elevation parameters reached by the confined water pressure and the confined water top elevation; and to obtain the foundation pit excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project; an impermeable layer thickness calculation module, used to calculate the thickness of the overlying impermeable layer based on the foundation pit excavation bottom elevation and the confined water top elevation; and an initial inrush safety factor calculation module, used to calculate the initial inrush safety factor based on the impermeable layer thickness, soil unit weight parameters, the elevation parameters reached by the confined water pressure, the foundation pit excavation bottom elevation, and the impermeable layer thickness.

[0132] Optionally, the soil shear strength calculation unit includes: a static earth pressure coefficient calculation module, used to determine the effective internal friction angle of the cohesive soil in the overlying impermeable layer through direct shear tests or triaxial consolidated undrained tests, and calculate the static earth pressure coefficient based on the effective internal friction angle; or, to retrieve the Poisson's ratio reference table for soil types, obtain the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculate the static earth pressure coefficient based on the Poisson's ratio parameter; and a soil shear strength calculation module, used to calculate the soil shear strength based on the cohesion, internal friction angle, initial inrush safety factor, soil unit weight parameter, and static earth pressure coefficient of the overlying impermeable soil.

[0133] Optionally, the lock pit confined water control device based on soil shear strength further includes: a geometric constraint coefficient calculation module, used to calculate the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable soil layer, and then obtain the perimeter and area of ​​the local deep pit and calculate the geometric constraint coefficient of the local deep pit; and a soil resistance parameter calculation unit, used to calculate the resistance parameters of the overlying impermeable soil layer based on the geometric constraint coefficient of the local deep pit, wherein the resistance parameters of the overlying impermeable soil layer are used to calculate the corrected heave stability safety factor.

[0134] Optionally, the lock pit confined water control device based on soil shear strength further includes: a pit segmentation module, used to segment the overall pit of the target lock pit project into multiple sub-pits before determining the impermeable soil reinforcement construction parameters based on the target pit combined intervention path; a sub-pit constraint coefficient calculation module, used to calculate the independent perimeter and area of ​​each sub-pit and calculate the geometric constraint coefficient of the sub-pit; a sub-pit selection module, used to sort the geometric constraint coefficients of all sub-pits and select a predetermined number of sub-pits in ascending order; and a sub-pit corrected heave stability safety factor calculation module. The first module is used to calculate the modified inrush stability safety factor of each selected sub-pit based on the geometric constraint coefficient, soil unit weight parameter, water unit weight parameter, and soil shear strength. The second module is used to determine whether the target lock pit project meets the inrush stability requirements if the modified inrush stability safety factor of the sub-pit is greater than the preset inrush stability threshold. If the modified inrush stability safety factor of the sub-pit is less than or equal to the preset inrush stability threshold, the target lock pit project does not meet the inrush stability requirements, and the number, size, and excavation sequence of the sub-pits are adjusted to ensure that effective lateral soil constraints are formed between adjacent sub-pits.

[0135] Optionally, the reinforcement construction parameter determination unit includes: a first construction parameter determination module, used to determine the parameters of the construction jet grouting pipe, grout parameters, and cohesion of the consolidated body when the target foundation pit combination intervention path is selected as high-pressure jet grouting cement sealing process, to obtain the first reinforcement construction parameters; a second construction parameter determination module, used to configure the grout water-cement ratio parameters, soil moisture content parameters, and curing age, to obtain the second reinforcement construction parameters; a grouting volume configuration module, used to configure the grouting volume of different construction jet grouting pipes; and a soil reinforcement construction parameter determination module, used to determine the impermeable layer soil reinforcement construction parameters based on the first reinforcement construction parameters, the second reinforcement construction parameters, and the grouting volume of different construction jet grouting pipes.

[0136] Optionally, the seepage prevention inspection unit includes: a seepage prevention inspection module, used to conduct seepage inspection on the lock foundation pit through in-situ seepage test strategy and seepage flow data monitoring strategy. The in-situ seepage test strategy includes: excavating a cofferdam at the seepage prevention wall or the junction of the seepage prevention wall and the soil of the target lock foundation pit project. The depth of the cofferdam penetrates the seepage prevention wall into the impermeable layer. Water is injected into the cofferdam to maintain a stable water head height, the amount of water replenished per unit time is recorded, and the permeability coefficient of the seepage prevention wall is calculated.

[0137] The aforementioned control device for pressurized water in the lock pit based on soil shear strength may also include a processor and a memory. The aforementioned pit parameter calculation unit 61, soil shear strength calculation unit 62, stability safety factor calculation unit 63, reinforcement construction parameter determination unit 64, and seepage prevention inspection unit 65 are all stored in the memory as program units. The processor executes the aforementioned program units stored in the memory to realize the corresponding functions.

[0138] The aforementioned processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and the control of confined water in the lock pit can be achieved by adjusting kernel parameters based on the soil shear strength.

[0139] The aforementioned memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0140] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored computer program, wherein, when the computer program is running, it controls the device where the computer-readable storage medium is located to execute any one of the above-described embodiments of the method for controlling confined water in a lock pit based on soil shear strength.

[0141] According to another aspect of the present invention, an electronic device is also provided, including one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method for controlling confined water in a lock pit based on soil shear strength as described in any of the above embodiments.

[0142] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for controlling confined water in a lock pit based on soil shear strength as described in various embodiments of this application.

[0143] This application also provides a computer program product, including a non-volatile computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for controlling confined water in a lock pit based on soil shear strength as described in various embodiments of this application.

[0144] Figure 7 This is a hardware structure block diagram of an electronic device (or mobile device) for implementing a method for controlling confined water in a lock pit based on soil shear strength, according to an embodiment of the present invention. Figure 7 As shown, an electronic device may include one or more ( Figure 7 The processor (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and memory 704 for storing data are also included. In addition, it may include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a keyboard, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 7 The structure shown is for illustrative purposes only and does not limit the structure of the electronic device described above. For example, the electronic device may also include components that are more... Figure 7 The more or fewer components shown, or having the same Figure 7 The different configurations shown.

[0145] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0146] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0147] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0148] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0149] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0150] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0151] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling confined water in a lock pit based on soil shear strength, characterized in that, include: Based on geological survey data and the elevation of the bottom surface of the excavation pit, the pressure water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor are calculated. Based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance, the shear strength of the soil is calculated. Based on the thickness of the impermeable overlying layer, the initial inrush safety factor, the geometric constraint coefficient of the local deep pit, the shear strength of the soil, and the confined water head, the modified inrush stability safety factor is calculated. If the corrected surge stability safety factor is less than the preset surge stability threshold, it is determined that the target lock foundation pit project does not meet the surge stability requirements. Based on the target foundation pit combined intervention path, the construction parameters for the impermeable soil reinforcement are determined. After construction is carried out according to the impermeable soil reinforcement construction parameters, a seepage inspection is conducted on the lock foundation pit. If the inspection results indicate that the wall seepage prevention requirements are met, the stability of the target lock foundation pit project is determined to meet the requirements.

2. The method for controlling confined water in a lock pit based on soil shear strength according to claim 1, characterized in that, The steps for calculating the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on geological survey data and the elevation of the excavated bottom surface include: Based on the geological survey data, multiple soil layer types distributed from top to bottom were determined, and the soil permeability coefficient corresponding to each soil layer type was determined by a pumping test strategy. The elevation parameters reached by the confined water pressure and the elevation of the confined water top plate were determined by using a confined water test strategy. The confined water head is calculated based on the elevation parameters reached by the confined water pressure and the elevation of the confined water roof. Obtain the excavation bottom elevation, soil unit weight parameters, and water unit weight parameters of the target lock foundation pit project; The thickness of the overlying impermeable layer is calculated based on the bottom elevation of the foundation pit and the top elevation of the confined water slab. The initial surge safety factor is calculated based on the thickness of the impermeable layer, the soil unit weight parameter, the elevation parameter reached by the confined water pressure, the bottom elevation of the foundation pit excavation, and the thickness of the impermeable layer.

3. The method for controlling confined water in a lock pit based on soil shear strength according to claim 2, characterized in that, The steps for calculating the shear strength of soil based on the pre-obtained cohesion and internal friction angle of the overlying impermeable soil layer include: The effective internal friction angle of the cohesive soil in the overlying impermeable layer is determined by direct shear test or triaxial consolidated undrained test, and the coefficient of earth pressure at rest is calculated based on the effective internal friction angle; or, Retrieve the Poisson's ratio reference table for soil types, obtain the Poisson's ratio parameter corresponding to the cohesive soil in the overlying impermeable layer, and calculate the at-rest earth pressure coefficient based on the Poisson's ratio parameter; The shear strength of the soil is calculated based on the cohesion, internal friction angle, initial heave safety factor, soil unit weight parameter, and static earth pressure coefficient of the overlying impermeable soil layer.

4. The method for controlling confined water in a lock pit based on soil shear strength according to claim 1, characterized in that, After calculating the shear strength of the soil based on the pre-obtained cohesion and internal friction angle of the overlying impermeable soil layer, the following steps are also included: Obtain the perimeter and area of ​​the local deep pit in the foundation pit, and calculate the geometric constraint coefficient of the local deep pit in the foundation pit; The resistance parameters of the overlying impermeable soil layer are calculated based on the geometric constraint coefficient of the local deep pit of the foundation pit, wherein the resistance parameters of the overlying impermeable soil layer are used to calculate the corrected heave stability safety factor.

5. The method for controlling confined water in a lock pit based on soil shear strength according to claim 1, characterized in that, Before determining the construction parameters for impermeable soil reinforcement based on the target foundation pit combined intervention path, the following steps are also included: The overall foundation pit of the target ship lock foundation pit project is divided into multiple sub-foundations; For each of the sub-foundation pits, calculate the independent perimeter and area of ​​the sub-foundation pit, and calculate the geometric constraint coefficient of the sub-foundation pit; Sort the geometric constraint coefficients of all the sub-foundations and select a predetermined number of sub-foundations in ascending order; Based on the geometric constraint coefficient, soil unit weight parameter, water unit weight parameter, and soil shear strength of each selected sub-foundation pit, the modified inrush stability safety factor of the sub-foundation pit is calculated. If the modified inrush stability safety factor of the sub-foundation pit is greater than the preset inrush stability threshold, it is determined that the target lock foundation pit project meets the inrush stability requirements. If the corrected inrush stability safety factor of the sub-foundation pit is less than or equal to the preset inrush stability threshold, it is determined that the target lock foundation pit project does not meet the inrush stability requirements. The number, size and excavation sequence of the sub-foundation pits are adjusted to ensure that effective lateral soil constraints are formed between adjacent sub-foundation pits.

6. The method for controlling confined water in a lock pit based on soil shear strength according to claim 1, characterized in that, The steps for determining the construction parameters for impermeable soil reinforcement based on the target foundation pit combined intervention path include: When the target foundation pit is selected as the combined intervention path of high-pressure jet grouting cement sealing process, the parameters of the jet grouting pipe, the grout parameters and the cohesion of the solidified body are determined to obtain the first reinforcement construction parameters. The second reinforcement construction parameters are obtained by configuring the grout water-cement ratio, soil moisture content, and curing age. Configure the grouting volume for different construction jet grouting pipes; Based on the first reinforcement construction parameters, the second reinforcement construction parameters, and the grouting volume of the different construction jet grouting pipes, the reinforcement construction parameters of the impermeable soil layer are determined.

7. The method for controlling confined water in a lock pit based on soil shear strength according to claim 1, characterized in that, After construction according to the aforementioned impermeable soil reinforcement parameters, the steps for conducting a permeability inspection of the lock foundation pit include: The in-situ permeability test strategy and the seepage flow data monitoring strategy are used to conduct permeability inspection on the lock foundation pit. The in-situ permeability test strategy includes: excavating a cofferdam at the seepage barrier wall or the junction of the seepage barrier wall and the soil of the target lock foundation pit project. The depth of the cofferdam penetrates the seepage barrier wall into the impermeable layer. Water is injected into the cofferdam to maintain a stable water head height. The amount of water added per unit time is recorded, and the permeability coefficient of the seepage barrier wall is calculated.

8. A device for controlling confined water in a lock pit based on soil shear strength, characterized in that, include: The foundation pit parameter calculation unit is used to calculate the confined water head, the thickness of the overlying impermeable layer, and the initial inrush safety factor based on geological survey data and the elevation of the bottom surface of the foundation pit excavation. The soil shear strength calculation unit is used to calculate the soil shear strength based on the cohesion and internal friction angle of the overlying impermeable soil layer obtained in advance. The stability safety factor calculation unit is used to calculate the corrected inrush stability safety factor based on the thickness of the overlying impermeable layer, the initial inrush safety factor, the geometric constraint factor of the local deep pit, the shear strength of the soil, and the confined water head. The reinforcement construction parameter determination unit is used to determine that the target lock foundation pit project does not meet the surge stability requirements when the corrected surge stability safety factor is less than the preset surge stability threshold, and to determine the reinforcement construction parameters of the impermeable soil layer based on the target foundation pit combined intervention path. The seepage prevention inspection unit is used to conduct seepage inspection on the lock foundation pit after construction is carried out according to the impermeable soil reinforcement construction parameters, and to determine that the stability of the target lock foundation pit project meets the requirements if the inspection results indicate that the seepage prevention requirements of the wall are met.

9. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method for controlling confined water in lock pits based on soil shear strength as described in any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for controlling confined water in a lock pit based on the shear strength of soil as described in any one of claims 1 to 7.

Images