A semi-analytical calculation method for the floating amount of a shield segment in soft soil with shallow overburden near a river

Abstract

The application discloses a kind of river soft weak shallow soil shield segment floating quantity semi-analytical calculation method, it is related to the technical field of shield tunnel construction mechanics quantitative calculation, and its technical solution points include the following steps: obtaining the geology hydrology parameters and construction working condition parameters of shield construction area, obtain the initial floating monitoring data of segment;According to the geology hydrology parameters and construction working condition parameters, generate the mechanical boundary condition set of segment initial stress state;According to the load constraint base of segment of mechanical boundary condition set, according to the initial floating monitoring data and time-varying displacement control relationship, obtain the time-varying displacement evolution result of segment floating;The time-varying displacement evolution result is corrected to obtain segment floating quantity data value, and the effect is to improve the safety control level of river soft weak shallow soil shield tunnel construction.

Description

Technical Field

[0001] This invention relates to the field of quantitative calculation technology of mechanical engineering in shield tunnel construction, and more specifically, it relates to a semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow overburdened soil near a river. Background Technology

[0002] In the field of shield tunnel construction in the Linjiang area with soft and shallow overburden, segment floating is a problem that threatens the tunnel forming quality and structural safety. The Linjiang area generally has engineering characteristics such as silty soft soil, high permeability of the stratum, hydraulic connection between river water and groundwater, and relatively small overburden thickness. Soft soil has significant rheological properties, and the groundwater level fluctuates periodically with the seasons. The buoyancy generated by the uncured grout at the shield tail, the unloading rebound of the stratum, and the multiple superposition of seepage loads can easily cause the segments to float continuously, leading to problems such as inter-ring misalignment, lining leakage, and excessive internal forces in the structure.

[0003] Traditional methods neglect key influencing factors such as the time-varying effect of groundwater seepage, long-term creep deformation of soft soil, disturbance layers during shield tunneling, and stress attenuation during grout consolidation. Furthermore, they cannot distinguish the stress transmission sequence of multiple media such as strata, grout, and tunnel segments, nor can they quantify the dynamic evolution of upward displacement. This results in significant deviations between calculated values ​​and long-term on-site monitoring data, enabling only rough qualitative judgments and making it difficult to support refined construction management. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-covered soil near rivers.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside areas includes the following steps: Obtain geological and hydrological parameters and construction condition parameters of the shield tunneling area, and obtain initial uplift monitoring data of the tunnel segments; A set of mechanical boundary conditions characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters. The load-constrained base of the tunnel segment is defined based on the set of mechanical boundary conditions, and the soil creep characteristics are obtained based on the rheological parameters of the soft strata. The action path of slurry stress in strata deformation is determined based on the load-constrained base and the soil creep characteristics. The time-varying displacement control relationship of the coordinated deformation of the segments, grout, and strata is determined based on the load-constrained base, soil creep characteristics, and action links. The time-varying displacement evolution result of the segment buoyancy is obtained based on the initial buoyancy monitoring data and the time-varying displacement control relationship; the time-varying displacement evolution result is corrected to obtain the segment buoyancy data value.

[0006] Preferably, the mechanical boundary condition set characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters, specifically including the following steps: Identify the characteristics of groundwater seepage and flow and the bearing capacity of weak soil layers based on geological and hydrological parameters; differentiate the degree of advance disturbance of shield tunneling and the pressure distribution range of grouting based on construction condition parameters; The radial stress interface of the tunnel segment is obtained based on the characteristics of groundwater seepage flow, the bearing capacity of weak soil layers, the degree of advance disturbance, and the pressure distribution range of grouting filling. The interface force form and force limit are determined based on the radial force interface, and the force forms and force limits of various interfaces are summarized to form a set of mechanical boundary conditions.

[0007] Preferably, the radial stress interface of the tunnel segment is obtained based on the characteristics of groundwater seepage flow, the bearing capacity of weak soil layers, the degree of advance disturbance, and the pressure distribution range of grouting filling. Specifically, this includes the following steps: The seepage effect layers of the strata are divided according to the characteristics of groundwater seepage flow; the bearing capacity of the soil layer is distinguished according to the bearing characteristics of the soft soil layer; the shield tunneling influence layer is determined according to the degree of advance disturbance; and the grout spreading and covering area is defined according to the pressure distribution range of grouting filling. The radial stress interface of the tunnel segment is obtained based on the strata affected by seepage, the areas of soil bearing strength, the layers affected by shield tunneling, and the area covered by grout.

[0008] Preferably, the load constraint base of the tunnel segment is defined according to the set of mechanical boundary conditions, specifically including the following steps: Based on the set of mechanical boundary conditions, the action levels of the self-weight of the soil and water around the pipe segment and the lifting load of grouting filling are distinguished. The load-restrained foundation is determined based on the site's soil cover, water level distribution, and the level of action.

[0009] Preferably, the soil creep characteristics are obtained based on the rheological parameters of the soft strata, specifically including the following steps: Based on the rheological properties of the soft strata, the instantaneous compressive deformation component and the time-delayed continuous deformation component of the soil were distinguished. Determine the first development rate and the first stability threshold corresponding to the instantaneous compressive deformation component; Determine the second evolution rate and the second stability threshold corresponding to the time-delayed continuous deformation component; The first growth rate, the first stability threshold, the second growth rate, and the second stability threshold are integrated to form the soil creep characteristics.

[0010] Preferably, determining the action path of slurry stress in formation deformation based on the load-constrained base and the soil creep characteristics specifically includes the following steps: The effective range of stress transmission between the stratum and the grouting slurry is determined based on the load-constrained base. The increase or decrease of water-soil coupling stress over time was determined based on the characteristics of soil creep. Based on the effective action range and the increase / decrease range, the transmission path of stress redistribution within the grout caused by soil deformation is decomposed to obtain the mechanical action link.

[0011] Preferably, the time-varying displacement control relationship of the segment, grout, and stratum co-deformation is determined based on the load-constrained base, soil creep characteristics, and action chain, specifically including the following steps: The deformation components of formation compression, grout consolidation, and segment uplift are obtained according to the transmission sequence of the action link. The deformation range of each deformation component is constrained by the load-constrained base. The deformation rate benchmark of each deformation component over time is determined by the soil creep characteristics. The variation trends of each deformation component are obtained based on the deformation rate benchmark and the action link; Based on the deformation range, trend of change, and force transmission characteristics of the action link, a time-varying displacement control relationship for the coordinated deformation of segments, slurry, and formation is constructed.

[0012] Preferably, the variation trend of each deformation component is obtained based on the deformation rate reference and the action link, specifically including the following steps: The deformation effect of each deformation component is superimposed based on the deformation rate benchmark; The linkage deformation characteristics of multi-level media are obtained by determining the force transmission sequence based on the action link and deformation effect. Based on the linkage deformation characteristics, the deformation coordination characteristics of the formation, slurry, and segments are obtained, and the variation trend of each deformation component is constrained by the deformation coordination characteristics.

[0013] Preferably, the time-varying displacement evolution result of the segment's upward movement is obtained based on the initial upward movement monitoring data and the time-varying displacement control relationship, specifically including the following steps: The deformation datum for calibrating the time-varying displacement control relationship is based on the initial ascent monitoring data; Based on the deformation datum, the displacement development trend of the segment uplift is determined, and the time-varying displacement evolution result of the segment uplift is obtained.

[0014] Preferably, the correction of the time-varying displacement evolution result to obtain the segment uplift data value specifically includes the following steps: Adjust the time-varying displacement evolution results based on the additional constraint effect generated by the creep of soft soil. The stress attenuation effect caused by the consolidation shrinkage of the grout was determined after adjusting the time-varying displacement evolution results. Based on the baseline deformation amplitude and stress attenuation effect, deviation compensation is performed to obtain the data value of segment float.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention establishes a standardized set of mechanical boundary conditions based on geological, hydrological, and construction parameters. It distinguishes the action levels of soil and water self-weight constraint loads and grouting lifting loads, delineates the interaction space of the load-constrained base locking medium, and then combines soil rheological parameters to decompose instantaneous compression and delayed creep deformation components. It fully restores the temporal link of stress transmission in the strata, grout, and tunnel segments. It corrects the deformation benchmark of time-varying displacement control relationship through initial uplift monitoring data, completes deviation compensation based on benchmark deformation amplitude, and finally outputs uplift data. This effectively reduces defects such as segment misalignment and joint leakage, and improves the safety management level of shield tunnel construction in soft and shallow overburden areas along rivers. Attached Figure Description

[0016] Figure 1 A flowchart illustrating a semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-covered soil near a river, as provided in this embodiment of the invention; Figure 2 This invention provides a flowchart illustrating the process of obtaining the set of mechanical boundary conditions using a semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside terrain, as part of an embodiment of the present invention. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0020] Reference Figures 1-2 As shown.

[0021] The embodiments further illustrate the semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow soil near rivers proposed in this invention.

[0022] A semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside areas includes the following steps: Obtain geological and hydrological parameters and construction condition parameters of the shield tunneling area, and obtain initial uplift monitoring data of the tunnel segments; A set of mechanical boundary conditions characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters. The load-constrained base of the tunnel segment is defined based on the set of mechanical boundary conditions, and the soil creep characteristics are obtained based on the rheological parameters of the soft strata. The action path of grout stress in strata deformation is determined based on the load-constrained base and soil creep characteristics. The time-varying displacement control relationship of the coordinated deformation of the segments, grout, and strata is determined based on the load-constrained base, soil creep characteristics, and action links. The time-varying displacement evolution of the tunnel segment is obtained based on the initial buoyancy monitoring data and the time-varying displacement control relationship; the buoyancy data value of the tunnel segment is obtained by correcting the time-varying displacement evolution results.

[0023] The mechanical boundary condition set characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters. This process includes the following steps: Identify the characteristics of groundwater seepage and flow and the bearing capacity of weak soil layers based on geological and hydrological parameters; differentiate the degree of advance disturbance of shield tunneling and the pressure distribution range of grouting based on construction condition parameters; The radial stress interface of the tunnel segment is obtained based on the characteristics of groundwater seepage flow, the bearing capacity of weak soil layers, the degree of advance disturbance, and the pressure distribution range of grouting filling. The specific steps include: The seepage effect layers of the strata are divided according to the characteristics of groundwater seepage flow; the bearing capacity of the soil layer is distinguished according to the bearing characteristics of the soft soil layer; the shield tunneling influence layer is determined according to the degree of advance disturbance; and the grout spreading and covering area is defined according to the pressure distribution range of grouting filling. The radial stress interface of the tunnel segment is obtained based on the stratum of seepage, the area of ​​soil bearing strength, the layer of shield tunneling influence, and the area covered by grout. The interface force form and force limit are determined based on the radial force interface, and the force forms and force limits of various interfaces are summarized to form a set of mechanical boundary conditions.

[0024] Geological and hydrological parameters include formation permeability coefficient, groundwater level depth, soil saturated unit weight, undrained shear strength of soil, and soil layer thickness. Based on all these indicators, the characteristics of groundwater seepage flow and the bearing capacity of weak soil layers are identified. Identification of groundwater seepage flow characteristics involves calculating the formation seepage force based on the formation permeability coefficient and groundwater level depth. Formation seepage force = permeability coefficient × hydraulic gradient × seepage area. The permeability coefficient is converted to meters per day, the seepage area is converted to square meters, and the final seepage force is expressed in kilonewtons (kN). Hydraulic gradient = Difference between river water level and tunnel center water level at the riverside site ÷ Horizontal distance of soil from tunnel to river body. The riverside area experiences periodic rises and falls in water level, and the hydraulic gradient value changes continuously at different times, corresponding to a synchronous increase or decrease in seepage force. This is used to divide the strata into multiple layers of seepage action. The bearing characteristics of weak soil layers are determined based on two indicators: saturated unit weight and undrained shear strength. Vertical self-sustaining bearing capacity of soil = undrained shear strength of soil × 2 + saturated unit weight of soil × overburden thickness. The unit of undrained shear strength of soil is kPa, the unit of saturated unit weight of soil is kN per cubic meter, the unit of overburden thickness is meter, and the unit of vertical self-sustaining bearing capacity of soil is kPa. The vertical self-supporting capacity of the soil is compared with the actual water and soil pressure around the tunnel segments. Areas with values ​​higher than the water and soil pressure are designated as areas with strong soil bearing capacity, while areas with values ​​lower than the water and soil pressure are designated as areas with weak soil bearing capacity. The soil at the bottom and lower sides of the tunnel in the soft, shallow overburden site near the river belongs to the area with weak bearing capacity, while the area with thicker overburden at the top of the tunnel belongs to the area with strong bearing capacity. The classification of these two types of areas determines the strength of the soil's constraint and support capacity for the tunnel segments.

[0025] Construction parameters include shield tunneling thrust, cutterhead excavation gap, tail grouting pressure, grouting diffusion distance, and grouting flow rate. All indicators are used to differentiate the degree of shield tunneling disturbance and the pressure distribution range of grouting. The degree of shield tunneling disturbance is determined by the shield tunneling thrust and cutterhead excavation gap. A greater shield tunneling thrust results in a larger cutterhead excavation gap and a wider range of cutting and squeezing disturbance to the soil. This determines the shield tunneling influence layers, which are divided into an inner, middle, and outer layer. The inner layer is tightly attached to the outer wall of the tunnel lining segments, with completely broken soil structure. The middle layer exhibits plastic deformation, while the outer layer only experiences minor elastic deformation. The radial thickness of each of the three layers is quantified according to the degree of tunneling disturbance. The distribution range of grouting pressure is determined by the synchronous grouting pressure and grout diffusion distance at the shield tail. The higher the grouting pressure, the farther the grout diffusion distance. This is used to define the grout spreading and covering area. In shallow overburden construction near the river, grouting prioritizes filling the gaps at the top and sides of the segments, while the grout spreading thickness at the bottom of the segments is smaller. The difference in grouting flow rate between different ring segments changes the circumferential length and radial thickness of the grout spreading and covering area. The grouting pressure gradually decreases radially outward.

[0026] The seepage layer corresponds to the contact range between groundwater and soil; the area of ​​weak soil bearing capacity corresponds to the contact range of undisturbed soil supporting the tunnel segments; the shield tunneling influence layer corresponds to the contact range between disturbed soil and tunnel segments; and the grout spreading and covering area corresponds to the contact range between uncured grout and the outer wall of the tunnel segments. The results of these four zoning categories are superimposed and integrated along the circumferential and radial directions of the tunnel segments. Overlapping areas are eliminated, and the medium contact boundary at each location is retained. This yields the circumferential and radial stress interfaces covering the entire outer wall of the tunnel segments. Each stress interface corresponds to the interaction between a single medium and the tunnel segment; there are no interfaces with mixed calculations of multiple loads. For example, the top interface of the tunnel segment belongs to both the grout spreading and covering area and the seepage layer, and is divided into the grout interaction interface and the seepage soil interaction interface. The bottom interface of the tunnel segment belongs only to the area of ​​weak soil bearing capacity and the inner tunneling layer, corresponding to the stress interface of a single disturbed soft soil.

[0027] The stress form is determined by the type of medium corresponding to the interface. The stress form of the interface under groundwater seepage is normal seepage pressure; the stress form of the interface under undisturbed soil support is vertical self-sustaining pressure and lateral earth pressure; the stress form of the interface under shield tunneling disturbance is plastic soil compression load; and the stress form of the interface under grout contact is grout buoyancy and grout filling pressure. The grout pressure limit of the grout interface = grout unit weight × grout spreading thickness, and grout pressure = grout saturated unit weight × grout spreading thickness. The saturated unit weight of grout is in kilonewtons per cubic meter, and the grout spreading thickness is in meters. Each radial stress interface corresponds to a unique set of stress forms and upper and lower limits. The upper limit is the maximum load value of the medium, and the lower limit is the minimum load value of the medium. During the rising water period near the river, the upper limit of the pressure at the seepage interface increases synchronously, and the upper limit of the pressure at the grout interface gradually decreases during the initial setting stage of grouting.

[0028] The stress forms and stress limits corresponding to all radial stress interfaces are summarized, and duplicate stress type data are eliminated. The data are then organized in an orderly manner according to soil loads, grout loads, and seepage loads to form a set of mechanical boundary conditions. The set of mechanical boundary conditions includes the location, type, and value range of all external loads during the segment construction stage, matching the dynamic load change characteristics of the soft and shallow overburden soil layer near the river.

[0029] Determining the load-constrained base of the tunnel segments based on the set of mechanical boundary conditions includes the following steps: Based on the set of mechanical boundary conditions, the action levels of the self-weight of the soil and water around the pipe segment and the lifting load of grouting filling are distinguished. The load-restrained foundation is determined based on the site's soil cover, water level distribution, and the level of action.

[0030] Based on the mechanical boundary condition set, the action levels corresponding to the soil and water self-weight and grouting lifting load around the tunnel segment are distinguished. The mechanical boundary condition set records the load type, load value, radial distance of load action, and circumferential coverage length at each radial interface of the tunnel segment. Soil and water self-weight is a constraint load that presses the tunnel segment downwards. This type of load originates from the self-weight accumulation of the stratum soil and groundwater. In the mechanical boundary condition set, it corresponds to the soil pressure and water pressure data of the original soil bearing interface and the seepage soil action interface. The action levels of soil and water self-weight are divided into the far-field stratum soil and water layer and the near-field disturbed soil and water layer according to the radial distance from far to near. The far-field stratum soil and water layer is located outside the tunneling influence circle, and the soil is not disturbed by construction. The soil and water self-weight pressure value is stable. The calculation formula for the far-field soil and water self-weight pressure is: Far-field soil and water self-weight pressure = soil saturated unit weight × total cover thickness + water unit weight × groundwater level depth. The soil saturated unit weight is converted to kilonewtons per cubic meter, and the total cover thickness is converted to kilonewtons per cubic meter. The unit of measurement is meters, the unit weight of water is taken as a fixed value of 10 kN per cubic meter, the groundwater level is converted to meters, and the unit of far-field soil and water self-weight pressure is kilopascals. The near-field disturbed soil and water layer is located within the shield tunneling influence zone, where the soil structure is fractured and porosity is increased, resulting in a reduction in the effective constraint pressure generated by the soil and water self-weight. The formula for calculating the near-field effective soil and water pressure is: Near-field effective soil and water pressure = Reduction coefficient × Far-field soil and water self-weight pressure. The reduction coefficient is determined based on the tunneling disturbance layer level. The reduction coefficients for the inner and outer concentric layers are 0.4 to 0.6, for the middle concentric layer 0.6 to 0.8, and for the outer concentric layer 0.8 to 0.95. The two types of soil and water action layers are arranged from the outside to the inside along the radial direction of the pipe segment, and all of them play a restraining role in limiting the upward lifting of the pipe segment. The total thickness of the soil cover in the shallow overburden site near the river is 3 to 8 meters. The thickness of the soil and water layer in the far field decreases synchronously with the thickness of the overburden, while the proportion of the disturbed soil and water layer in the near field increases accordingly, and the restraining ability of the soil and water self-weight is significantly weakened.

[0031] Grouting and filling lifting load is an upward buoyancy load that propels the tunnel segments upward. This upward buoyancy load originates from the self-weight buoyancy of the unsolidified grout at the shield tail and the grouting pressure. Based on the mechanical boundary condition set, the grout pressure data corresponds to the interface of the grout spreading and covering area. The grouting and filling lifting load is divided into a fresh liquid grout layer and a semi-solidified grout transition layer according to the grout solidification sequence and radial spreading range. The fresh liquid grout layer adheres tightly to the outer wall of the tunnel segments, and the grout has not undergone consolidation shrinkage, possessing complete lifting buoyancy. The formula for calculating the liquid grout lifting pressure is: Liquid grout lifting pressure = Saturated unit weight of grout × Radial thickness of grout spreading. The saturated unit weight of grout is in kilonewtons per cubic meter, and the radial thickness of grout spreading is converted to meters. The liquid grout pressure is calculated using the following formula: Liquid grout lifting pressure = Saturated unit weight of grout × Radial thickness of grout spreading. The pressure is kPa; the semi-consolidated grout transition layer is located outside the liquid grout layer. The grout gradually releases water, causing consolidation and shrinkage, and the uplift pressure continuously decreases. The formula for calculating the semi-consolidated grout pressure is: semi-consolidated grout pressure = attenuation coefficient × liquid grout uplift pressure. The attenuation coefficient decreases synchronously with the time elapsed after grouting. The attenuation coefficient is 0.9 after 1 hour of grouting, 0.6 after 3 hours of grouting, and 0.3 after 6 hours of grouting. The two types of grouting action layers are distributed close to the outer wall of the pipe segment and are located inside the near-field disturbed soil and water layer. The groundwater seepage rate is fast in the riverside strata, and the water loss rate of the grout is even faster. The attenuation coefficient of the semi-consolidated grout layer is smaller than that of the conventional inland strata, and the uplift load attenuates faster.

[0032] The load-constrained base is determined by considering the site's soil cover conditions, water level distribution, and the layers of action. The site's soil cover conditions include the total soil cover thickness, the thickness of each soil layer, the thickness of the soil cover at the top of the tunnel, and the thickness of the underlying soil layer at the bottom of the tunnel. The soil cover thickness directly determines the radial boundary of the far-field soil and water self-weight constraint layer. When the total soil cover thickness is small, the radial boundary of the far-field soil and water layer contracts towards the outer wall of the tunnel segment, and the upper boundary of the load-constrained base is close to the tunnel segment. If the thickness of the underlying soft soil layer at the bottom of the tunnel is large, the soil bearing capacity is insufficient, and the lower boundary of the load-constrained base extends downward, falling within the creep constraint range of the underlying soft soil. The water level distribution includes the stable groundwater level elevation, the periodic fluctuation difference of the river water level, and the vertical range of the seepage layer. The groundwater level elevation determines the calculation benchmark for water pressure. The rise and fall of the river water level changes the vertical thickness of the seepage layer. During periods of rising water level, the seepage layer expands upward, and the upper boundary of the load-constrained base expands upward in sync. During periods of falling water level, the seepage layer contracts, and the upper boundary of the base falls back in sync.

[0033] The radial and circumferential coverage areas of the spatial boundaries corresponding to the soil cover conditions and water level distribution, the layers of soil and water self-weight action, and the layers of grouting and filling lifting load action are superimposed and integrated. Redundant boundaries in the overlapping areas of multiple load levels are eliminated, and a closed spatial outline that simultaneously contains constraint loads and buoyancy loads is retained. This closed spatial outline is the load-constrained base. The load-constrained base wraps around the outer wall of the tunnel segment circumferentially, extends radially outward to the boundary of the undisturbed strata in the far field, extends vertically upward to the top of the seepage layer corresponding to the groundwater level, and extends vertically downward to the interface of the stable bearing soil layer at the bottom of the tunnel. The base contains the far-field soil and water layer, the near-field disturbed soil and water layer, the liquid grout layer, and the semi-consolidated grout layer. For example, the total thickness of the tunnel overburden is 5 meters, the groundwater level is 1 meter below the surface, the radial thickness of the shield tunneling influence layer is 1.2 meters, the maximum radial thickness of the grout spreading is 0.3 meters, and after superimposing various boundary loads, the upper boundary of the load-constrained base reaches the water level line 1 meter below the surface, the lower boundary extends to the stable silty clay layer 2 meters below the bottom of the tunnel, the radial outer boundary is 1.2 meters away from the outer wall of the segment, the radial inner boundary is close to the outer wall of the segment, and the circumferentially completes the 360-degree circumferential coverage of the segment.

[0034] The soil creep characteristics are obtained based on the rheological parameters of weak strata, specifically including the following steps: Based on the rheological properties of the soft strata, the instantaneous compressive deformation component and the time-delayed continuous deformation component of the soil were distinguished. Determine the first development rate and the first stability threshold corresponding to the instantaneous compressive deformation component; Determine the second evolution rate and the second stability threshold corresponding to the time-delayed continuous deformation component; The first growth rate, the first stability threshold, the second growth rate, and the second stability threshold are integrated to form the soil creep characteristics.

[0035] Based on the rheological parameters of soft strata, the soil is divided into instantaneous compressive deformation components and delayed continuous deformation components. These parameters include the instantaneous elastic compressive modulus, long-term creep modulus, creep decay time, pore water seepage rate, and initial void ratio. The two types of deformation components are distinguished by the deformation initiation time and deformation after load application. The instantaneous compressive deformation component corresponds to the soil compression deformation that occurs instantaneously during shield tunneling and grouting pressure application. Under load, the pores within the soil are rapidly squeezed, and a small amount of pore water is expelled in a short time. This component is dominated by the instantaneous elastic compressive modulus and initial void ratio. In shallow overburden tunnels near rivers, the disturbed soft soil tightly adhering to the outer side of the tunnel segments undergoes instantaneous compressive deformation at the moment of grouting pressure application. This deformation does not continue to increase over time. The delayed continuous deformation component corresponds to the slow creep deformation of soil under long-term stable load. During the continuous load process, pore water in the soil slowly and continuously seeps out, and soil particles gradually slide and reorganize. This component is dominated by the long-term creep modulus of the soil, the creep decay time of the soil, and the rate of pore water seepage and discharge. The continuous seepage of groundwater in the riverside area accelerates the discharge of pore water. The development cycle of delayed continuous deformation is 2 to 3 times longer than that of dry inland strata.

[0036] The two types of deformation components are independently superimposed. The total soil deformation = instantaneous compressibility deformation + delayed continuous deformation. The instantaneous compressibility deformation and delayed continuous deformation are converted to millimeters. This can distinguish the contribution ratio of the two types of deformation to the overall soil compression. For example, when a load is applied to a riverside project for 10 minutes, the total soil deformation is 8 millimeters, of which the instantaneous compressibility deformation is 6 millimeters and the delayed continuous deformation is 2 millimeters. After the load is applied for 72 hours, the total soil deformation is 16 millimeters. The instantaneous compressibility deformation remains at 6 millimeters and does not change. The delayed continuous deformation increases to 10 millimeters, reflecting the time difference between the two types of components.

[0037] The first development rate and first stability threshold corresponding to the instantaneous compressive deformation component are determined. The first development rate represents the amount of deformation generated by instantaneous compressive deformation per unit time in the initial stage of load application. The first development rate = total instantaneous compressive deformation ÷ total time to complete instantaneous deformation. The unit of total instantaneous compressive deformation is millimeters, and the unit of total time to complete instantaneous deformation is minutes. The total time to complete instantaneous deformation of soft soil strata is between 5 and 15 minutes. Silt-clay soil has a higher porosity and a larger total instantaneous compressive deformation, corresponding to a higher first development rate value. The first stability threshold represents the maximum limit deformation value that instantaneous compressive deformation can achieve. When the soil deformation value reaches the first stability threshold, the instantaneous compressive deformation no longer increases. The first stability threshold = average additional stress inside the load-constrained base ÷ instantaneous elastic compressive modulus of the soil × calculated thickness of soil compression. The unit of average additional stress inside the load-constrained base is converted to kilopascals, the unit of instantaneous elastic compressive modulus of the soil is kilopascals, and the unit of calculated thickness of soil compression is millimeters. For example, the average additional stress inside the load-constrained base is equal to 120 kPa, the instantaneous elastic compression modulus of the soil is equal to 4000 kPa, the calculated thickness of the soil for compression is equal to 2000 mm, and the first stability threshold is equal to 120 ÷ 4000 × 2000 = 60 mm, which means that the instantaneous compression deformation can produce a maximum deformation of 60 mm. After exceeding this value, the instantaneous deformation will no longer develop.

[0038] The second development rate and the second stability threshold corresponding to the time-delayed continuous deformation component were determined. The second development rate represents the amount of deformation that is slowly generated by the time-delayed continuous deformation per unit time. This value gradually decreases as the deformation time progresses. The second development rate = initial time-delayed deformation increment ÷ single-segment timing duration. The unit of the initial time-delayed deformation increment is millimeters, and the unit of the single-segment timing duration is converted to hours. In the soft and water-rich strata near the river, the pore water drains quickly, and the value of the second development rate is larger in the early stage of load application. As the pore water is gradually drained, the second development rate continues to decrease. The second stability threshold represents the deformation limit that the soil can approach after long-term sustained deformation. When the soil's delayed deformation value approaches the second stability threshold, soil creep essentially stops. This value is calculated based on the soil's long-term creep modulus and additional stress. The corresponding formula is: Second stability threshold = Average additional stress inside the load-constrained base ÷ Long-term creep modulus of soil × Compressibility calculation thickness of soil. The average additional stress inside the load-constrained base is converted to kPa, the long-term creep modulus of soil is converted to kPa, and the compressibility calculation thickness of soil is converted to millimeters. In the same riverside silty soft soil project, the long-term creep modulus of soil is equal to 1200 kPa. With other calculation parameters remaining unchanged, the second stability threshold is calculated to be 120 ÷ 1200 × 2000 = 200 mm, representing a delayed sustained deformation limit of 200 mm.

[0039] Soil creep characteristics are formed by integrating the first development rate, the first stability threshold, the second development rate, and the second stability threshold. The integration process categorizes these four indicators according to their deformation time sequence. The first group of creep parameters, which includes the first development rate and the first stability threshold, represents the instantaneous deformation that occurs rapidly upon load application. The second group of creep parameters, which includes the second development rate and the second stability threshold, represents the slow-developing deformation that occurs over a long period under load. The soil creep characteristics simultaneously record all values ​​from both groups of parameters, comprehensively covering the entire deformation pattern of the soil from the initial stage of load application to the long-term stable stage. This allows for the description of the entire process of deformation changes in soft strata over time. It can calculate the immediate uplift of tunnel segments caused by instantaneous soil compression within a short period of load application, and can also extrapolate the delayed uplift increment of tunnel segments caused by continuous soil creep over several days after construction completion.

[0040] The action path of grout stress in formation deformation is determined based on the load-constrained base and soil creep characteristics, specifically including the following steps: The effective range of stress transmission between the stratum and the grouting slurry is determined based on the load-constrained base. The increase or decrease of water-soil coupling stress over time was determined based on the characteristics of soil creep. Based on the effective action range and the increase / decrease range, the transmission path of stress redistribution within the grout caused by soil deformation is decomposed to obtain the mechanical action link.

[0041] The effective range of stress transmission between the stratum and the grout is determined based on the load-constrained base. The load-constrained base delineates all closed spatial boundaries around the tunnel segment involved in the stress calculation. The effective range is the overlapping area where the soil and grout inside the base directly contact each other and can transmit interaction forces. Radial and circumferential boundary parameters of the load-constrained base are extracted. The inner radial boundary is close to the outer wall of the tunnel segment, and the outer radial boundary extends to the undisturbed original soil. The circumferential boundary completely covers the 360-degree range of the tunnel segment. Independent spatial contours of the grout spreading coverage area and the soil bearing area inside the base are extracted separately. The overlapping spatial range of these two contours is the common contact surface for stress transmission. The effective range includes radial thickness and circumferential coverage length parameters. The radial thickness equals the radial thickness of the grout spreading. The circumferential coverage length is divided according to the circumferential angle of the tunnel segment. Under the condition of shallow overburden near the river, the grout spreading is sufficient in the top 180-degree range of the tunnel segment, resulting in a larger circumferential coverage length value. The grout spreading is weak at the bottom of the tunnel segment, resulting in a smaller circumferential coverage length value. The effective contact area = circumferential coverage length of the effective contact area × radial calculated perimeter of the effective contact area. The circumferential coverage length is in meters, and the radial calculated perimeter is in meters. This area represents the complete contact surface where the deformation of the stratum soil can directly act on the grout. There is no direct stress exchange between the soil outside the contact surface and the grout. For example, the circumferential coverage length of the effective contact area of ​​a single ring segment of a riverside tunnel is 6 meters, and the radial calculated perimeter is 3.14 meters. Substituting these values ​​into the calculation, the effective contact area is 6 × 3.14 = 18.84 square meters.

[0042] The increase and decrease of soil-water coupled stress over time are determined based on the characteristics of soil creep. The soil creep characteristics record the first development rate and the first stability threshold corresponding to instantaneous compressive deformation, and the second development rate and the second stability threshold corresponding to delayed continuous deformation. Soil-water coupled stress is a comprehensive external load formed by the superposition of the soil's self-weight and the seepage force of groundwater. When soil undergoes compressive creep, the soil pore volume shrinks, and the soil-water coupled stress changes synchronously with the deformation process. The increase and decrease are used to quantify the fluctuation value of soil-water coupled stress. First, two independent time intervals are divided. The first interval is the instantaneous deformation period, and its duration corresponds to the total time for the instantaneous compressive deformation to complete. The second interval is the delayed creep period, and its duration covers the entire cycle from the completion of instantaneous deformation to the soil deformation approaching stability. The instantaneous soil-water stress increment = first development rate × soil compression thickness per unit time × soil unit weight. The first development rate is in millimeters per minute, the soil compression thickness per unit time is in meters, and the soil unit weight is in kilonewtons per cubic meter. This value represents the stress increase during the rapid compression of the soil at the initial stage of load application. The delayed soil-water stress attenuation = second development rate × cumulative creep duration × pore water permeability reduction coefficient. The pore water permeability reduction coefficient for water-rich strata near the river is between 0.6 and 0.8. The delayed soil-water stress attenuation is in kilopascals, representing the stress decrease caused by the discharge of pore water and weakening of soil constraints during long-term creep. Real-time soil-water coupling stress = initial soil-water coupling stress + instantaneous soil-water stress increment - delayed soil-water stress attenuation.

[0043] By combining the effective action range and the magnitude of increase and decrease in water-soil coupling stress, the transmission path of stress redistribution within the grout caused by soil deformation is decomposed, and the mechanical action link is finally obtained. The force transmission path is broken down according to the order of force transmission from the outside to the inside and from the soil to the grout. The first layer of the transmission path is the compression creep deformation of the external soil under the action of water-soil coupling stress. The deformation only occurs within the contact surface range defined by the effective action zone. The deformation of the soil outside the zone cannot be transmitted to the grout. The second layer of the transmission path is the application of a compressive load to the grout through the contact surface of the effective action zone by the soil compression deformation. The real-time value of the compressive load is calculated by the real-time water-soil coupling stress and the contact area of ​​the effective action zone. The corresponding calculation formula is: Grout compressive force applied to the soil = Real-time water-soil coupling stress × Contact area of ​​the effective action zone. The unit of real-time water-soil coupling stress is kPa, and the unit of effective action zone contact area is square meters. The third layer of the transmission path is the redistribution of stress inside the grout after being squeezed by the soil. The stress rises in the top area of ​​the grout and the stress attenuates in the bottom area. The magnitude of the stress redistribution matches the increase or decrease of the water-soil coupling stress over time. During the instantaneous deformation period, the overall stress of the grout rises rapidly, and during the delayed creep period, the overall stress of the grout falls slowly. The three-layered transmission paths are connected and integrated in sequence according to time, and the corresponding relationships of medium, load, deformation and stress changes in each layer are recorded to form the mechanical action link of slurry stress in formation deformation.

[0044] The time-varying displacement control relationship of the coordinated deformation of the segments, grout, and strata is determined based on the load-constrained base, soil creep characteristics, and action chain. This includes the following steps: The deformation components of formation compression, grout consolidation, and segment uplift are obtained according to the transmission sequence of the action link. The deformation range of each deformation component is constrained by the load-constrained base. The deformation rate benchmark of each deformation component over time is determined by the soil creep characteristics. Based on the deformation rate benchmark and the action link, the variation trend of each deformation component is obtained, specifically including the following steps: The deformation effect of each deformation component is superimposed based on the deformation rate benchmark; The linkage deformation characteristics of multi-level media are obtained by determining the force transmission sequence based on the action link and deformation effect. Based on the linkage deformation characteristics, the deformation coordination characteristics of the formation, slurry, and segments are obtained, and the variation trend of each deformation component is constrained by the deformation coordination characteristics. Based on the deformation range, trend of change, and force transmission characteristics of the action link, a time-varying displacement control relationship for the coordinated deformation of segments, slurry, and formation is constructed.

[0045] The deformation components of the mechanical action chain are broken down into ground compression, grout consolidation, and segment lifting according to the force transmission sequence. The spatial boundaries for deformation of each type of deformation component are defined based on the load-constrained base. The deformation rate benchmark corresponding to the time development of each deformation component is determined based on the soil creep characteristics. The transmission sequence of the mechanical action chain follows a transmission logic from the outside to the inside. The external ground soil first undergoes compressive deformation under the water-soil coupling load. The compressive force generated by the ground compression is transmitted to the grout layer, triggering grout consolidation and shrinkage deformation. The buoyancy and filling pressure changes within the grout ultimately act on the segments, driving them to undergo upward lifting deformation. The load-constrained base is used to limit the deformation range of the three types of deformation components. Formation compression deformation can only occur within the soil action zone defined by the base; undisturbed soil outside the base and not included in the calculation does not undergo compression deformation. The range of grout consolidation deformation matches the grout spreading and covering area inside the base. Segment uplift deformation only occurs within the circumferential and radial boundaries where the outer wall of the segment contacts the grout; areas exceeding the base space are not included in any deformation calculation. Soil creep characteristics include a first development rate corresponding to instantaneous compression and a second development rate corresponding to delayed creep. These are used to calibrate the deformation rate benchmarks for the three types of deformation components in the two stages. The deformation rate benchmark for the instantaneous deformation stage is derived from the first development rate, and the deformation rate benchmark for the delayed creep stage is derived from the second development rate. Formation compression deformation = Formation compression deformation rate benchmark × Cumulative application time. The unit of formation compression deformation rate benchmark is converted to millimeters per hour, and the unit of cumulative application time is hours. Grout consolidation deformation = Grout consolidation deformation rate benchmark × Cumulative application time. The grout consolidation deformation rate benchmark continuously decreases as the grout solidifies. The water loss rate of grout in the river-rich formation is faster, and the grout consolidation deformation value is higher than that of conventional formations under the same application time. Single-period segment uplift increment = Segment uplift deformation rate benchmark × Cumulative application time. The calculation formulas for the three types of deformation components are independent of each other, and all deformation values ​​cannot exceed the spatial limit deformation threshold defined by the load-constrained base. For example, the benchmark for the formation compression deformation rate during the instantaneous deformation stage is 0.6 mm per hour, and the cumulative duration is 1 hour. Substituting these values ​​into the calculation, the formation compression deformation is 0.6 × 1 = 0.6 mm. The benchmark for the grout consolidation deformation rate is 0.3 mm per hour, and the grout consolidation deformation is 0.3 × 1 = 0.3 mm for the same duration. The benchmark for the segment uplift deformation rate is 0.4 mm per hour, and the segment uplift increment in a single time period is 0.4 × 1 = 0.4 mm.

[0046] Based on the deformation rate benchmark, the deformation effects generated independently by various deformation components are superimposed. The superposition calculation formula is: Total deformation effect of medium = Formation compression deformation + Grout consolidation deformation + Segment uplift increment. The units of the three types of deformation are millimeters, and the unit of the total deformation effect of medium is millimeters. This can obtain the total deformation amplitude generated by the superposition of multiple media at a single moment. In the instantaneous deformation stage, the three types of deformation increase synchronously, and the total deformation effect of medium continues to rise. In the delayed creep stage, the formation compression rate gradually slows down, the grout consolidation continues to shrink, and the growth rate of the total deformation effect of medium continues to narrow. By combining the force transmission sequence of the mechanical action link with the total deformation effect of the superimposed medium, the linkage deformation characteristics of multi-level media are determined. The mechanical action link stipulates that stratum compression is the pre-cause of grout consolidation, and grout consolidation is the direct cause of segment uplift. The deformation of the three types of media does not develop independently. The soil compression load generated by stratum compression amplifies the shrinkage amplitude of grout consolidation, and the buoyancy attenuation of grout consolidation reduces the incremental segment uplift. For example, for every 1 mm increase in stratum compression deformation, the grout consolidation deformation increases by 0.2 mm simultaneously, and for every 1 mm increase in grout consolidation deformation, the incremental segment uplift decreases by 0.15 mm simultaneously. This linkage correlation value is fixedly calibrated by the rheological parameters of the soft stratum near the river. Based on the multi-level media linkage deformation characteristics, the deformation coordination characteristics of the formation, slurry, and segments are derived. The deformation coordination characteristics are used to limit the upper and lower limits of the values ​​of the three types of deformation components to prevent the unlimited growth of a single deformation component from deviating from the actual stress state of the formation. The deformation coordination characteristics simultaneously constrain the change trend of each type of deformation component. When the formation compression deformation is close to the first stability threshold, the deformation rate benchmark corresponding to the formation compression is adjusted down synchronously, and the growth trend of the segment uplift component slows down synchronously. When the slurry consolidation deformation is close to the slurry stable shrinkage threshold, the segment uplift component changes from continuous increase to slow decline.

[0047] By integrating the deformation range, the variation trends of each component, and the complete force transmission characteristics within the mechanical action link, a time-varying displacement control relationship for the coordinated deformation of the grout formation in the tunnel lining is established. The deformation range is locked by the load-constrained base, serving as the spatial boundary constraint condition for the control relationship; the variation trends of each component are jointly defined by the soil creep characteristics, the multi-layer medium linkage deformation characteristics, and the deformation coordination characteristics, serving as the time evolution constraint condition for the control relationship; the force transmission characteristics of the mechanical action link define the order of occurrence of the three types of deformation and the quantitative ratio of their interaction, serving as the mechanical coupling constraint condition for the control relationship. Total time-varying segment uplift displacement = Total increment of segment uplift during the initial instantaneous stage + Total increment of segment uplift during the later delayed creep stage. Total increment of segment uplift during the initial instantaneous stage = Total deformation of formation compression during the instantaneous stage × Formation-to-grout force transmission coefficient + Total deformation of grout consolidation during the instantaneous stage × Grout-to-segment buoyancy transmission coefficient. Total increment of segment uplift during the later delayed creep stage = Cumulative deformation of formation compression during the delayed stage × Formation creep reduction transmission coefficient - Cumulative shrinkage of grout consolidation during the delayed stage × Grout buoyancy attenuation coefficient.

[0048] The time-varying displacement evolution of the tunnel lining segments is obtained based on the initial uplift monitoring data and the time-varying displacement control relationship. The specific steps include: The deformation datum for calibrating the time-varying displacement control relationship is based on the initial ascent monitoring data; Based on the deformation datum, the displacement development trend of the segment uplift is determined, and the time-varying displacement evolution result of the segment uplift is obtained.

[0049] The deformation benchmark of the time-varying displacement control relationship is calibrated based on the initial uplift monitoring data. The initial uplift monitoring data consists of measured displacement values ​​collected by field monitoring equipment shortly after the shield tail grouting is completed. This includes the measured uplift displacement of the tunnel segments at 0.5 hours, 1 hour, and 2 hours after grouting. All monitored displacement values ​​are converted to millimeters. The deformation benchmark is the initial displacement zero point and initial uplift increment benchmark used within the time-varying displacement control relationship to initiate displacement calculations. Before calibration, the deformation benchmark is calculated solely based on geological and grouting theoretical parameters, resulting in a fixed difference from the actual initial deformation on site. Measured data is required for matching and correction. First, the theoretical initial uplift value of the time-varying displacement control relationship at the same timing duration is extracted. The initial theoretical uplift value = total formation compression deformation in the instantaneous stage × formation-to-grout force transmission coefficient + total grout consolidation deformation in the instantaneous stage × grout-to-segment buoyancy transmission coefficient. The initial uplift monitoring values ​​collected on site at the same duration are then extracted. The benchmark correction difference = initial theoretical uplift value - initial uplift monitoring value. This difference represents the fixed offset between the theoretical model and the actual on-site measurements. Substituting the benchmark correction difference into all displacement calculation items of the time-varying displacement control relationship, the overall translation calibration of the deformation benchmark is completed. The calibrated deformation benchmark calculation is: the single-period segment uplift increment after calibration = the original single-period segment uplift increment - the benchmark correction difference. For example, after 1 hour of grouting, the initial theoretical float value calculated through the time-varying displacement control relationship is 4.2 mm, while the initial on-site float monitoring value during the same period is 3.4 mm. The benchmark correction difference is 4.2 - 3.4 = 0.8 mm. The 0.8 mm offset value is deducted from the segment uplift increment calculation for all durations to complete the unified calibration of the deformation benchmark and eliminate the calculation deviation in the initial stage of the theoretical model. In riverside sites, local fluctuations in grouting flow and uneven disturbance of shallow soft soil are prone to occur. The benchmark correction difference for different ring segments varies from 0.3 mm to 1.2 mm. Each ring segment uses the initial float monitoring data of the corresponding ring to calibrate a dedicated deformation benchmark.

[0050] Based on the calibrated deformation benchmark, the displacement development trend of the entire segment uplift process is determined, thus obtaining the time-varying displacement evolution result of the segment uplift. The calibrated deformation benchmark locks the initial zero point and initial uplift increment for displacement calculation. Starting from this, the displacement development trend is deduced in two stages. The first stage is the instantaneous uplift development stage, corresponding to 0 to 12 hours after grouting. During this stage, the soil is instantaneously compressed, and the liquid buoyancy of the grout acts simultaneously, resulting in a continuous and rapid increase in the segment uplift displacement, which is shown as an upward curve. The second stage is the delayed creep development stage, corresponding to 12 to 72 hours after grouting. During this stage, the delayed creep of the soil progresses slowly, the grout gradually consolidates and shrinks, the buoyancy continuously decreases, and the growth rate of the segment uplift displacement continuously slows down. Under some working conditions, the displacement may slightly decline, and the displacement development trend is shown as a slowing convergence curve. Based on the calibrated time-varying displacement control relationship, displacement values ​​for two stages were calculated time-by-time. The time-varying displacement of the segment uplift at any given moment = cumulative uplift increment in the instantaneous stage after calibration + cumulative uplift increment in the delayed stage after calibration. The units for both the instantaneous and delayed stages after calibration are millimeters. The segment uplift displacement values ​​corresponding to different construction durations were summarized time-by-time, and all calculated values ​​were arranged in chronological order. The displacement rise and fall patterns from the initial moment of grouting completion to the soil creep approaching stability were recorded. The entire set of orderly arranged displacement values ​​represents the time-varying displacement evolution result of the segment uplift. This evolution result reflects the entire process of segment uplift in the soft, shallow-covered soil site near the river, characterized by rapid initial rise followed by slow convergence. It includes both the instantaneous uplift peak in a short time and the delayed uplift increment due to long-term creep, and can intuitively reflect the dynamic evolution of segment uplift under the coupling of multiple factors such as river water level fluctuations, soft soil rheology, and grout consolidation.

[0051] The correction of the time-varying displacement evolution results to obtain the segment uplift data value includes the following steps: Adjust the time-varying displacement evolution results based on the additional constraint effect generated by the creep of soft soil. The stress attenuation effect caused by the consolidation shrinkage of the grout was determined after adjusting the time-varying displacement evolution results. Based on the baseline deformation amplitude and stress attenuation effect, deviation compensation is performed to obtain the data value of segment float.

[0052] The time-varying displacement evolution results are adjusted based on the additional constraint effect generated by the creep of soft soil. Under continuous load, the soft soil undergoes delayed creep deformation, and the soil particles are continuously squeezed and reorganized. The density of the soil around the tunnel segment gradually increases, forming an additional constraint load that presses down on the tunnel segment. This constraint effect continuously offsets part of the upward displacement of the tunnel segment. The time-varying displacement evolution results of the foundation do not take into account the displacement reduction caused by this constraint, so the first round of numerical adjustment is required. Based on the characteristics of soil creep, the additional constraint stress of soil corresponding to different durations is extracted. The additional constraint stress of soil = second development rate × cumulative creep duration × equivalent unit weight of soil compression. The second development rate is converted to millimeters per hour, the cumulative creep duration is in hours, and the equivalent unit weight of soil compression is in kilonewtons per cubic meter. The corresponding displacement reduction is calculated based on the additional constraint stress of soil. Soil creep displacement reduction = additional constraint stress of soil ÷ equivalent stiffness of tunnel segment × calculation width of tunnel segment. The unit of additional constraint stress of soil is kilopascal, the unit of equivalent stiffness of tunnel segment is kilopascal per millimeter, and the unit of calculation width of tunnel segment is millimeters. The displacement value after soil constraint adjustment = original time-varying displacement evolution result value - soil creep displacement reduction value. The units of the original time-varying displacement evolution result value and the soil creep displacement reduction value are millimeters. The effect of soil additional constraint increases continuously with creep duration, and the corresponding displacement reduction value increases synchronously and gradually. For example, after 72 hours of grouting, the original time-varying displacement evolution result is 14.6 mm, and the soil creep displacement reduction is 3.2 mm. Substituting these values ​​into the calculation, the displacement value after soil constraint adjustment is 14.6 - 3.2 = 11.4 mm. This directly reflects the constraint effect brought about by long-term creep of soft soil, thus significantly reducing the calculated value of segment uplift. Long-term seepage of groundwater in the riverside site accelerates the soil creep process. Under the same time period, the soil creep displacement reduction is 30% to 50% higher than that of dry inland strata.

[0053] As time passes, the liquid grout filling the shield tail undergoes consolidation and shrinkage due to the release of internal water, resulting in a reduction in the overall volume of the grout. This leads to a continuous decrease in the filling stress that provides the lifting buoyancy within the grout. This stress attenuation weakens the upward lifting force of the tunnel segments, constituting a second factor affecting displacement correction. The grout consolidation stages are divided according to the cumulative time after grouting completion: liquid stage, semi-consolidation stage, and fully consolidated stage. Different stages correspond to different stress attenuation ranges. The real-time effective lifting stress of the grout is calculated as: initial grouting filling stress × grout consolidation attenuation coefficient. The attenuation coefficient is 0.92 after 1 hour of grouting, 0.65 after 12 hours, and 0.31 after 72 hours. The unit for the real-time effective lifting stress of the grout is kPa. The grout shrinkage displacement attenuation is calculated by converting the difference between the real-time effective uplift stress and the initial grouting stress. Grout shrinkage displacement attenuation = initial uplift displacement increment × (initial grouting stress - real-time effective uplift stress) ÷ initial grouting stress. The unit of the initial uplift displacement increment is millimeters, and the units of the stress difference and the initial grouting stress are kilopascals (kPa). This value represents the additional reduction in segment uplift after grout consolidation and shrinkage. For example, if the initial uplift displacement increment after 72 hours of grouting is 10 millimeters, the initial grouting stress is 200 kPa, and the real-time effective uplift stress is 62 kPa, the grout shrinkage displacement attenuation is calculated to be 10 × (200 - 62) ÷ 200 = 6.9 millimeters, reflecting that long-term grout consolidation and shrinkage reduces the segment uplift.

[0054] By combining the baseline deformation amplitude and stress attenuation effect for overall deviation compensation, the final value of the segment uplift data is obtained. The baseline deformation amplitude is the initial displacement baseline value locked when calibrating the deformation baseline using the initial uplift monitoring data. It represents the true uplift baseline when there is no significant creep or grout consolidation shrinkage in the early stage of on-site grouting, and is used to balance the excessive reduction deviation caused by the two-layer correction. Deviation compensation is divided into superimposing the attenuation amount of the two-layer correction, correcting the excessive reduction according to the baseline deformation amplitude, and merging the total displacement reduction amplitude caused by the two types of attenuation. The total displacement reduction amplitude = soil creep displacement reduction amount + grout shrinkage displacement attenuation amount. The units of the two types of reduction values ​​are millimeters, and the unit of the total displacement reduction amplitude is millimeters. Deviation compensation is performed based on the benchmark deformation amplitude. The segment uplift data value = displacement value after soil constraint adjustment - grout shrinkage displacement attenuation + benchmark deformation amplitude compensation value. The benchmark deformation amplitude compensation value is calculated from the matching difference between the benchmark deformation amplitude and the total displacement reduction amplitude. When the total displacement reduction amplitude is greater than the benchmark deformation amplitude, the compensation value is positive to offset the problem of low value caused by overcorrection. When the total displacement reduction amplitude is less than the benchmark deformation amplitude, the compensation value is negative. For example, the displacement value after soil constraint adjustment is equal to 11.4 mm, the grout shrinkage displacement attenuation is equal to 6.9 mm, and the benchmark deformation amplitude compensation value is equal to 1.3 mm. Substituting these values ​​into the calculation, the final segment uplift data value is equal to 11.4 - 6.9 + 1.3 = 5.8 mm. This fully matches the long-term uplift evolution law of the soft, shallow, water-rich soil strata near the river and can serve as a quantitative reference value for on-site segment uplift control, grouting parameter optimization, and tunnel structure safety verification.

[0055] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside areas, characterized in that... Includes the following steps: Obtain geological and hydrological parameters and construction condition parameters of the shield tunneling area, and obtain initial uplift monitoring data of the tunnel segments; A set of mechanical boundary conditions characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters. The load-constrained base of the tunnel segment is defined based on the set of mechanical boundary conditions, and the soil creep characteristics are obtained based on the rheological parameters of the soft strata. The action path of slurry stress in strata deformation is determined based on the load-constrained base and the soil creep characteristics. The time-varying displacement control relationship of the coordinated deformation of the segments, grout, and strata is determined based on the load-constrained base, soil creep characteristics, and action links. The time-varying displacement evolution results of the segment floating are obtained based on the initial floating monitoring data and the time-varying displacement control relationship; The time-varying displacement evolution results are corrected to obtain the segment uplift data value.

2. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 1, is characterized in that... The mechanical boundary condition set characterizing the initial stress state of the tunnel segments is generated based on geological and hydrological parameters and construction condition parameters. This process includes the following steps: Identify the characteristics of groundwater seepage and flow and the bearing capacity of weak soil layers based on geological and hydrological parameters; differentiate the degree of advance disturbance of shield tunneling and the pressure distribution range of grouting based on construction condition parameters; The radial stress interface of the tunnel segment is obtained based on the characteristics of groundwater seepage flow, the bearing capacity of weak soil layers, the degree of advance disturbance, and the pressure distribution range of grouting filling. The interface force form and force limit are determined based on the radial force interface, and the various interface force forms and force limits are summarized to form a mechanical boundary condition set.

3. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 2, is characterized in that... Based on the characteristics of groundwater seepage flow, the bearing capacity of weak soil layers, the degree of advance disturbance, and the pressure distribution range of grouting filling, the radial stress interface of the segment in the circumferential direction is obtained, specifically including the following steps: The seepage effect layers of the strata are divided according to the characteristics of groundwater seepage flow; the bearing capacity of the soil layer is distinguished according to the bearing characteristics of the soft soil layer; the shield tunneling influence layer is determined according to the degree of advance disturbance; and the grout spreading and covering area is defined according to the pressure distribution range of grouting filling. The radial stress interface of the tunnel segment is obtained based on the strata affected by seepage, the areas of soil bearing strength, the layers affected by shield tunneling, and the area covered by grout.

4. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 1, is characterized in that... Determining the load-constrained base of the tunnel segments based on the set of mechanical boundary conditions includes the following steps: Based on the set of mechanical boundary conditions, the action levels of the self-weight of the soil and water around the pipe segment and the lifting load of grouting filling are distinguished. The load-restrained foundation is determined based on the site's soil cover, water level distribution, and the level of action.

5. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 1, is characterized in that... The soil creep characteristics are obtained based on the rheological parameters of weak strata, specifically including the following steps: Based on the rheological properties of the soft strata, the instantaneous compressive deformation component and the time-delayed continuous deformation component of the soil were distinguished. Determine the first development rate and the first stability threshold corresponding to the instantaneous compressive deformation component; Determine the second evolution rate and the second stability threshold corresponding to the time-delayed continuous deformation component; The first growth rate, the first stability threshold, the second growth rate, and the second stability threshold are integrated to form the soil creep characteristics.

6. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 1, is characterized in that... The action path of grout stress in formation deformation is determined based on the load-constrained base and the soil creep characteristics, specifically including the following steps: The effective range of stress transmission between the stratum and the grouting slurry is determined based on the load-constrained base. The increase or decrease of water-soil coupling stress over time was determined based on the characteristics of soil creep. Based on the effective action range and the increase / decrease range, the transmission path of stress redistribution within the grout caused by soil deformation is decomposed to obtain the mechanical action link.

7. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 1, is characterized in that... The time-varying displacement control relationship of the coordinated deformation of the tunnel segments, grout, and strata is determined based on the load-constrained base, soil creep characteristics, and action chain. This includes the following steps: The deformation components of formation compression, grout consolidation, and segment uplift are obtained according to the transmission sequence of the action link. The deformation range of each deformation component is constrained by the load-constrained base. The deformation rate benchmark of each deformation component over time is determined by the soil creep characteristics. The variation trends of each deformation component are obtained based on the deformation rate benchmark and the action link; Based on the deformation range, trend of change, and force transmission characteristics of the action link, a time-varying displacement control relationship for the coordinated deformation of segments, slurry, and formation is constructed.

8. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened soil near a river, as described in claim 7, is characterized in that... Based on the deformation rate benchmark and the action link, the variation trend of each deformation component is obtained, specifically including the following steps: The deformation effect of each deformation component is superimposed based on the deformation rate benchmark; The linkage deformation characteristics of multi-level media are obtained by determining the force transmission sequence based on the action link and deformation effect. Based on the linkage deformation characteristics, the deformation coordination characteristics of the formation, slurry, and segments are obtained, and the variation trend of each deformation component is constrained by the deformation coordination characteristics.

9. The semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside terrain according to claim 1, characterized in that, The time-varying displacement evolution result of the segment's upward movement is obtained based on the initial upward movement monitoring data and the time-varying displacement control relationship, specifically including the following steps: The deformation datum for calibrating the time-varying displacement control relationship is based on the initial ascent monitoring data; Based on the deformation datum, the displacement development trend of the segment uplift is determined, and the time-varying displacement evolution result of the segment uplift is obtained.

10. A semi-analytical calculation method for the uplift of shield tunnel segments in soft, shallow-overburdened riverside terrain, as described in claim 1, is characterized in that... The correction of the time-varying displacement evolution results to obtain the segment uplift data value specifically includes the following steps: Adjust the time-varying displacement evolution results based on the additional constraint effect generated by the creep of soft soil. The stress attenuation effect caused by the consolidation shrinkage of the grout was determined after adjusting the time-varying displacement evolution results. Based on the baseline deformation amplitude and stress attenuation effect, deviation compensation is performed to obtain the data value of segment float.

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