Earth pressure balance spoil pack prevention method and system

Abstract

The application discloses a kind of earth pressure balance slag prevention methods and systems, it is related to earth pressure balance slag improvement technical field, wherein, the method includes: based on shield construction site information, confirm tunneling area, and obtain the permeability coefficient, lateral compression modulus and slag density of shield slag in current tunneling area;According to permeability coefficient, lateral compression modulus and slag density, the consolidation coefficient of shield slag in screw conveyor is calculated;Obtain the construction characteristic parameter of tunneling area, and based on construction characteristic parameter and consolidation coefficient, the water-soil separation characterization factor of shield slag is calculated;Construction characteristic parameter at least includes: construction parameter and equipment operating parameter;According to water-soil separation characterization factor, the water-soil state determination result of shield slag is output, and based on water-soil state determination result, corresponding water-soil state early warning information is generated.The method can greatly reduce the risk of slag blocking, thereby improving the shield tunneling efficiency.

Description

Technical Field

[0001] This invention generally relates to the field of earth pressure balance soil improvement technology, and specifically to an earth pressure balance soil blockage prevention method and system. Background Technology

[0002] With the rapid development of urban underground rail transit and water diversion tunnels, the number of newly built earth pressure balance shield tunnels is increasing dramatically. During the excavation of an earth pressure balance shield tunnel, the soil cut by the cutterhead enters the soil chamber and acts as a support medium to resist the water and soil pressure in front of the tunnel face. However, due to the complexity and variability of the strata, the shield may encounter the problem of auger conveyor blockage when passing through cohesive strata.

[0003] Currently, control measures for screw conveyor blockage mainly rely on monitoring lagging operating parameters such as screw conveyor torque and slag discharge pressure, combined with the subjective judgment of tunnel boring machine operators. This results in control measures being significantly passive and delayed, often intervening only after a blockage trend has formed. This is not only inefficient but also makes it difficult to accurately control the dosage of additives, leading to cost waste or secondary risks. Therefore, engineering practice urgently needs a method that can provide early warning and quantitative prediction of screw conveyor blockage risks. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a method and system for preventing soil blockage by earth pressure balance.

[0005] In a first aspect, the present invention provides a method for preventing soil blockage due to earth pressure balance, comprising:

[0006] Based on the information of the shield tunneling site, the tunneling area is identified, and the permeability coefficient, lateral compression modulus, and density of the shield excavated soil in the current tunneling area are obtained.

[0007] Based on the permeability coefficient, lateral compression modulus, and soil density, the consolidation coefficient of the shield tunneling excavated soil in the screw conveyor is calculated.

[0008] The construction characteristic parameters of the tunneling area are obtained, and the water-soil separation characterization factor of the shield tunnel excavation soil is calculated based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operating parameters;

[0009] Based on the water and soil separation characterization factors, the water and soil status determination results of the shield tunneling excavated soil are output, and based on the water and soil status determination results, corresponding water and soil status early warning information is generated.

[0010] According to the technical solution provided by the present invention, based on the information of the shield tunneling construction site, the tunneling area is identified, and the permeability coefficient, lateral compression modulus, and density of the shield excavated soil within the current tunneling area are obtained, including:

[0011] Obtain the shield tunneling site information and confirm the tunneling area based on the shield tunneling site information; the shield tunneling site information includes at least: the area code of each tunneling area;

[0012] Obtain the area code of the current tunneling area, and based on the area code, call the shield excavation feature calibration database to obtain the permeability coefficient, lateral compression modulus and excavation density of the shield excavation in the current tunneling area;

[0013] The shield tunneling excavation soil characteristic calibration database is established by conducting permeability and compression tests on each shield tunneling excavation soil sample; the shield tunneling excavation soil characteristic calibration database includes at least: different regional codes and the permeability coefficient, lateral compression modulus, and soil density of the shield tunneling excavation soil corresponding to each regional code.

[0014] According to the technical solution provided by the present invention, construction characteristic parameters of the tunneling area are obtained, and water-soil separation characterization factors of the shield tunneling excavation are calculated based on the construction characteristic parameters and consolidation coefficient, including:

[0015] The construction parameters and equipment operating parameters are obtained; the construction parameters include: the excavation radius of the shield tunnel and the soil loosening coefficient; the equipment operating parameters include: the radius of the screw conveyor and the tunneling speed of the shield machine.

[0016] Based on the excavation radius, the loosening coefficient of the stratum, the radius of the screw conveyor, and the tunneling speed of the tunnel boring machine, the characteristic velocity of the tunnel excavation material in the screw conveyor is calculated.

[0017] Based on the characteristic velocity, consolidation coefficient, and screw conveyor radius, the water-soil separation characterization factor of the shield tunnel excavation soil is calculated.

[0018] According to the technical solution provided by the present invention, based on the water and soil separation characterization factor, the water and soil state determination result of the shield tunneling excavated soil is output, and based on the water and soil state determination result, corresponding water and soil state early warning information is generated, including:

[0019] Obtain the water-soil separation characterization factors;

[0020] If the water and soil separation characterization factor is less than the first preset threshold, the water and soil state determination result is that the shield tunneling slag will undergo water and soil separation.

[0021] If the water and soil separation characterization factor is greater than or equal to the first preset threshold and less than or equal to the second preset threshold, then the water and soil status determination result is that the shield tunneling slag is at risk of water and soil separation.

[0022] If the water and soil separation characterization factor is greater than the second preset threshold, then the water and soil state determination result is that the shield tunneling slag will not undergo water and soil separation.

[0023] Based on the obtained water and soil condition assessment results, corresponding water and soil condition early warning information is generated.

[0024] According to the technical solution provided by the present invention, after generating corresponding soil and water condition early warning information based on the obtained soil and water condition determination result, the method further includes:

[0025] Obtain the warning content information presented by the water and soil condition warning information; the warning content information includes at least: the water and soil condition determination result and the value of the water and soil separation characterization factor;

[0026] Based on the water and soil condition determination results and the values ​​of the water and soil separation characterization factors, the corresponding water and soil condition adjustment strategy is activated.

[0027] According to the technical solution provided by the present invention, based on the soil and water state determination result and the value of the soil and water separation characterization factor, a corresponding soil and water state adjustment strategy is activated, including:

[0028] If the soil and water condition determination result indicates that soil and water separation will occur in the shield tunnel excavation, then the first soil and water condition adjustment strategy is activated; the first soil and water condition adjustment strategy is to inject foam into the shield tunnel excavation according to the first preset injection ratio.

[0029] If the soil and water condition determination result indicates that there is a risk of soil-water separation in the shield tunnel excavation soil, then the second soil and water condition adjustment strategy is activated; the second soil and water condition adjustment strategy is to inject foam into the shield tunnel excavation soil using a gradual injection mode.

[0030] According to the technical solution provided by the present invention, when conducting permeability and compression tests on the shield tunneling soil samples, the pressure environment in the permeability and compression tests is consistent with that of the shield tunneling construction site.

[0031] Secondly, the present invention provides an earth pressure balance slag blockage prevention system, comprising:

[0032] The acquisition module is used to identify the tunneling area based on the shield tunneling site information, and to acquire the permeability coefficient, lateral compression modulus and density of the shield excavated soil in the current tunneling area.

[0033] The calculation module is used to calculate the consolidation coefficient of the shield tunneling excavated soil in the screw conveyor based on the permeability coefficient, the lateral compression modulus, and the soil density.

[0034] Furthermore, the calculation module is also used to obtain the construction characteristic parameters of the tunneling area, and to calculate the water and soil separation characterization factor of the shield tunnel excavation based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operating parameters;

[0035] The early warning module is used to output the water and soil status determination result of the shield tunneling excavated soil according to the water and soil separation characterization factor, and generate corresponding water and soil status early warning information based on the water and soil status determination result.

[0036] In summary, this technical solution specifically discloses a method and system for preventing soil blockage caused by earth pressure balance. The method includes: identifying the tunneling area based on shield tunneling site information and obtaining the permeability coefficient, lateral compression modulus, and density of the shield excavated soil within the current tunneling area; calculating the consolidation coefficient of the shield excavated soil in the screw conveyor based on the permeability coefficient, lateral compression modulus, and density; obtaining construction characteristic parameters of the tunneling area and calculating the water-soil separation characterization factor of the shield excavated soil based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least construction parameters and equipment operating parameters; outputting the water-soil state determination result of the shield excavated soil based on the water-soil separation characterization factor, and generating corresponding water-soil state early warning information based on the water-soil state determination result.

[0037] Compared with the prior art, the beneficial effects of the above-mentioned technical solution of the present invention are as follows:

[0038] This invention successfully constructs an early warning system for preventing muck blockage in tunnel boring machines (TBMs) by introducing a water-soil separation characterization factor, a quantitative indicator. This method calculates a water-soil separation characterization factor that matches the current muck volume based on key soil parameters and construction characteristic parameters corresponding to the tunneling area. This provides a reliable theoretical basis for predicting muck blockage, significantly reducing the risk of blockage and improving TBM tunneling efficiency. Furthermore, the data based on the water-soil separation characterization factor can provide a scientific basis for foam injection during subsequent TBM tunneling, guiding precise muck improvement and avoiding material waste due to excessive foam injection or severe cutterhead wear due to insufficient foam injection. This extends equipment life and reduces maintenance and replacement costs. Attached Figure Description

[0039] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0040] Figure 1This is a flowchart illustrating a method for preventing soil blockage using earth pressure balance.

[0041] Figure 2 This is a flowchart illustrating step S300 in an earth pressure balance method for preventing soil blockage.

[0042] Figure 3 This is a schematic diagram of a soil pressure balance system for preventing soil blockage.

[0043] The diagram is labeled as follows: 600, Prevention System; 601, Acquisition Module; 602, Calculation Module; 603, Early Warning Module. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] Example 1

[0047] To make the technical solutions of the embodiments of the present invention clearer and easier to understand, the application background of the embodiments of the present invention will be introduced below.

[0048] With the rapid development of urban underground rail transit and water diversion tunnels, the number of newly built earth pressure balance shield tunnels is increasing dramatically. During the excavation of an earth pressure balance shield tunnel, the soil cut by the cutterhead enters the soil chamber and acts as a support medium to resist the water and soil pressure in front of the tunnel face. Due to the complex and varied strata, the shield may encounter the problem of auger conveyor blockage when passing through cohesive strata.

[0049] However, in traditional methods, the control measures taken to address the blockage problem of screw conveyors mainly rely on monitoring lagging operating parameters such as screw conveyor torque and slag discharge pressure, combined with the subjective experience judgment of tunnel boring machine operators. This reliance makes the control measures highly subjective and lagging. Usually, human intervention is only taken when a serious blockage occurs, which not only wastes manpower and material resources, but also seriously restricts the efficiency of tunnel boring construction.

[0050] To address this problem, this invention proposes a method for preventing muck blockage using earth pressure balance. This method includes: identifying the tunneling area based on shield tunneling site information and obtaining the permeability coefficient, lateral confined compression modulus, and muck density of the shield muck within the current tunneling area; calculating the consolidation coefficient of the shield muck in the screw conveyor based on the permeability coefficient, lateral confined compression modulus, and muck density; obtaining construction characteristic parameters of the tunneling area and calculating the water-soil separation characterization factor of the shield muck based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least construction parameters and equipment operating parameters; outputting the water-soil state determination result of the shield muck based on the water-soil separation characterization factor, and generating corresponding water-soil state early warning information based on the water-soil state determination result. As can be seen, this invention, by calculating the water-soil separation characterization factor of the shield muck, assesses the possibility of muck blockage in advance and generates corresponding water-soil state early warning information in a timely manner for situations with blockage risk, so that subsequent muck improvement parameters can be adjusted for blockage prevention, thereby mitigating the risk of muck blockage in the shield screw conveyor to a certain extent.

[0051] Please refer to the following. Figure 1 The flowchart shown in this embodiment illustrates a method for preventing soil blockage using earth pressure balance. The implementing entity in this embodiment can be an intelligent soil blockage prevention and control system. This system integrates a sensor module, a data processing and calculation module, and a decision-making and control module. These three modules coordinate with each other to achieve closed-loop control. The following is a further explanation of each step of this invention. The prevention method includes the following steps:

[0052] S100. Based on the shield tunneling site information, confirm the tunneling area and obtain the permeability coefficient, lateral compression modulus, and density of the shield excavated soil in the current tunneling area.

[0053] Due to the complex and varied geological conditions at the tunnel boring machine (TBM) construction site, the entire tunnel route is usually divided into different geological units or construction sections during construction. Therefore, it is necessary to identify the corresponding tunneling area and then obtain the key soil parameters of the corresponding tunneling area.

[0054] The permeability coefficient, lateral compression modulus, and density of the tunnel boring machine (TBM) excavated soil can be determined by combining the geological survey report with the real-time location of the TBM to pinpoint the target analysis range. Experimental methods can then be used to accurately measure the permeability coefficient, lateral compression modulus, and density of the excavated soil, providing accurate and reliable input data for subsequent calculations.

[0055] The permeability coefficient is an indicator used to measure the ability of construction waste to allow water to flow through it. Generally, the lower the permeability coefficient, the more difficult it is for water to drain, and the more easily it forms a mud cake under pressure, leading to blockage. The lateral confined compression modulus is an indicator used to measure the ability of construction waste to resist compressive deformation under lateral confinement conditions. Generally, the higher the modulus, the more difficult it is to compress the construction waste under the pressure of a screw conveyor, the higher the pore water pressure, and the more likely water-soil separation will occur. Construction waste density is used in the subsequent calculation of the consolidation coefficient and reflects the basic physical properties of the construction waste.

[0056] Further, the specific process of step S100 is as follows: obtain shield tunneling site information and confirm the tunneling area based on the shield tunneling site information; the shield tunneling site information includes at least: the area code of each tunneling area; obtain the area code of the current tunneling area, and according to the area code, call the shield excavation soil characteristic calibration database to obtain the permeability coefficient, lateral compression modulus and excavation soil density of the shield excavation soil in the current tunneling area.

[0057] The shield tunneling muck characteristic calibration database was established by conducting permeability and compression tests on various shield tunneling muck samples. The shield tunneling muck characteristic calibration database includes at least: different regional codes and the permeability coefficient, lateral compression modulus, and muck density of the shield tunneling muck corresponding to each regional code.

[0058] Specifically, information about the tunnel boring machine (TBM) construction site is mainly obtained by reviewing geological survey reports and conducting on-site surveys before TBM construction. The tunneling area can be pre-divided according to the survey report so that it can be accurately assessed in segments and at different times. In order to distinguish different tunneling areas, different tunneling areas can be numbered to obtain a regional code corresponding to each tunneling area.

[0059] Original soil samples from different strata were obtained along tunnel lines coded in different regions, and these original soil samples were prepared into shield tunneling muck samples to simulate the muck state after actual tunneling. Subsequently, permeability and compression tests were conducted to calibrate the permeability coefficient, lateral confined compression modulus, and muck density corresponding to the actual shield tunneling muck samples. At the same time, during the permeability and compression tests, the confining pressure and axial pressure applied by the test equipment must be consistent with the water and soil pressure of the actual shield tunneling site in that area, because the mechanical and permeability properties of soil are strongly correlated with the pressure applied. Only the data measured under simulated in-situ pressure conditions can truly reflect the behavior of the muck under the high-pressure environment of the screw conveyor.

[0060] Finally, the three key parameters of shield excavation soil obtained from the experiment—permeability coefficient, lateral compression modulus, and soil density—were bound to the unique regional code of each tunneling area and entered into the database, thus forming a shield excavation soil characteristic calibration database, as shown in Table 1 below;

[0061] Table 1. Example of the database structure for identifying the characteristics of tunnel boring machine excavated soil.

[0062]

[0063] In practical applications, the intelligent prevention and control system for muck blockage can automatically identify the code of the area currently being excavated by the tunnel boring machine (TBM) using its real-time mileage or ring number. The system uses this area code as a query command to automatically request the TBM muck feature calibration database. Upon receiving the request, the database quickly returns the pre-stored permeability coefficient, lateral confined compression modulus, and muck density corresponding to that area code. The penetration coefficients corresponding to different regional codes. The lateral compression modulus corresponding to different region codes; The density of slag and soil corresponding to different regional codes; the above constants You can choose 1, 2, 3, or 4.

[0064] S200. Based on the permeability coefficient, lateral confined compression modulus, and soil density, the consolidation coefficient of the shield tunneling excavated soil in the screw conveyor is calculated.

[0065] Specifically, the permeability coefficient is denoted as The confined compressive modulus is denoted as The density of the slag is recorded as Finally, the consolidation coefficient is calculated using the following formula (1);

[0066] Formula (1);

[0067] in, It is the acceleration due to gravity; is the consolidation coefficient.

[0068] Here, the consolidation coefficient, as a key parameter in soil mechanics, comprehensively reflects the ability of slag soil to dissipate pore water pressure quickly after being subjected to stress.

[0069] S300. Obtain the construction characteristic parameters of the tunneling area, and calculate the water and soil separation characterization factor of the shield tunneling excavation based on the construction characteristic parameters and consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operation parameters;

[0070] In step S300, by combining the consolidation coefficient used to characterize the properties of the slag with construction conditions (such as tunneling speed, equipment size, etc.), a single index that can quantitatively reflect the antagonistic relationship between the flow effect and the drainage consolidation effect is calculated, namely the soil-water separation characterization factor, thereby quantifying the blockage risk and providing effective data reference for the subsequent generation of soil-water status early warning information.

[0071] Specifically, see Figure 2 Step S300 specifically includes the following steps:

[0072] S301. Obtain construction parameters and equipment operating parameters; among which, construction parameters include: the excavation radius of the shield tunnel and the loosening coefficient of the stratum; equipment operating parameters include: the radius of the screw conveyor and the tunneling speed of the shield machine;

[0073] Here, the excavation radius of the shield tunnel and the radius of the screw conveyor determine the shrinkage ratio of the excavated soil flow from the tunnel face to the screw conveyor; the soil loosening coefficient reflects the degree of volume expansion of the excavated soil after excavation; and the tunneling speed of the shield machine determines the amount of excavated soil entering the soil chamber and the screw conveyor per unit time. These parameters can be directly obtained from engineering requirements and pre-recorded properties of the actual soil and equipment, enabling real-time calculation of water and soil separation characterization factors.

[0074] S302. Based on the excavation radius, the loosening coefficient of the stratum, the radius of the screw conveyor, and the tunneling speed of the tunnel boring machine, the characteristic velocity of the tunnel excavation material in the screw conveyor is calculated.

[0075] S303. Based on the characteristic velocity, consolidation coefficient, and screw conveyor radius, the water and soil separation characterization factor of the shield tunnel slag is calculated.

[0076] Specifically, the excavation radius of the shield tunnel is denoted as... The formation looseness coefficient is denoted as The tunneling speed of the tunnel boring machine is denoted as... The radius of the screw conveyor is denoted as The characteristic velocity is finally calculated using the following formula (2);

[0077] Formula (2);

[0078] in, The characteristic velocity of the tunnel boring machine excavated soil in the screw conveyor; and this characteristic velocity This represents the average flow velocity of the slag in the screw conveyor.

[0079] Furthermore, based on characteristic velocity Consolidation coefficient and screw conveyor radius The water-soil separation characterization factor can be calculated using the following formula (3):

[0080] Formula (3);

[0081] in, This is a water-soil separation characterization factor, which can be used as the Peckley constant for shield tunneling excavated soil in a screw conveyor. It intuitively characterizes the antagonistic relationship between the flow effect and drainage consolidation effect of the shield tunneling excavated soil in the screw conveyor. For example, A small value means that the drainage consolidation effect is much faster than the flow effect. The shield tunnel excavated soil has enough time to lose water, consolidate, and thicken before being discharged, which can cause blockage of the screw conveyor. A large value means that the flow effect is dominant, the tunnel boring machine excavation is discharged quickly, and there is no time for drainage and consolidation, thus maintaining the flow state and preventing blockage in the screw conveyor.

[0082] S400: Based on the water and soil separation characterization factors, output the water and soil status determination results of the shield tunneling excavated soil, and generate corresponding water and soil status early warning information based on the water and soil status determination results.

[0083] After obtaining the water and soil separation characterization factors, based on theoretical analysis and extensive engineering practice, a critical threshold for the water and soil separation characterization factors can be set. The water and soil status judgment result of the current shield tunneling muck can be output by the relationship between the real-time value of the water and soil separation characterization factors and the critical threshold. For example, the shield tunneling muck may experience water and soil separation, the shield tunneling muck may be at risk of water and soil separation, or the shield tunneling muck may not experience water and soil separation. Corresponding water and soil status early warning information can be generated based on such water and soil status judgment results.

[0084] It should be noted that the form of water and soil condition early warning information can be adjusted according to the actual situation. For example, based on different water and soil condition assessment results, similar level prompts such as high risk, medium risk, and no risk can be issued. In this way, the water and soil condition early warning information can be made more intuitive.

[0085] Specifically, the process of outputting the water and soil status assessment results of shield tunnel excavation soil based on the water and soil separation characterization factors, and generating corresponding water and soil status early warning information based on the water and soil status assessment results, includes the following:

[0086] Scenario 1: After obtaining the water and soil separation characterization factor, if the water and soil separation characterization factor is less than the first preset threshold, the water and soil status determination result is that water and soil separation will occur in the shield tunnel slag.

[0087] Scenario 2: After obtaining the water and soil separation characterization factor, if the water and soil separation characterization factor is greater than or equal to the first preset threshold and less than or equal to the second preset threshold, the water and soil status determination result is that there is a risk of water and soil separation in the shield tunnel slag.

[0088] Scenario 3: After obtaining the water and soil separation characterization factor, if the water and soil separation characterization factor is greater than the second preset threshold, the water and soil status determination result is that the shield tunneling slag will not undergo water and soil separation.

[0089] Based on the above-obtained water and soil condition assessment results, corresponding water and soil condition early warning information is generated. For example, if the water and soil condition assessment result indicates that water and soil separation will occur with the shield tunnel excavation, a water and soil condition early warning information with a high-risk warning is issued; if the water and soil condition assessment result indicates that there is a risk of water and soil separation with the shield tunnel excavation, a water and soil condition early warning information with a medium-risk warning is issued; if the water and soil condition assessment result indicates that water and soil separation will not occur with the shield tunnel excavation, a water and soil condition early warning information with a no-risk warning is issued.

[0090] Furthermore, the relationship between the first preset threshold and the second preset threshold is that the first preset threshold is less than the second preset threshold. For example, the first preset threshold can be 1 and the second preset threshold can be 10, but there is no special limitation. These two values ​​need to be set according to the key soil parameters of the actual tunneling area, and calibration tests are also required in the early stage to obtain more accurate water and soil condition judgment results.

[0091] For example, the first preset threshold is set to 1 and the second preset threshold is set to 10:

[0092] when When this happens, it is determined that the tunnel boring machine's excavated soil will undergo drainage behavior. At this time, the excavated soil will separate into water and soil, causing blockage in the screw conveyor.

[0093] when If the tunnel boring machine's excavated soil is in the transitional stage from drainage to non-drainage, there is a possibility of soil-water separation, and there is a risk of blockage in the screw conveyor.

[0094] when If the conditions are met, it is determined that the slag will not drain, the slag will not separate into water and soil, and the slag can be discharged from the screw conveyor in a controllable manner without causing blockage.

[0095] To further improve the accuracy of early warning, in a preferred embodiment, the method can also introduce a critical void ratio as an auxiliary factor when determining the soil and water condition of the tunnel boring machine (TBM) excavated soil. Specifically, the critical void ratio represents the void ratio at which the soil volume neither shrinks (shear contraction) nor expands (shear dilatation) under a fixed effective confining pressure and shear stress. It is a state threshold used to characterize the shear deformation characteristics of the soil and can be obtained by conducting indoor triaxial shear tests on TBM excavated soil samples. The void ratio is the ratio of the pore volume to the soil particle volume. This is because the void ratio changes when the TBM excavated soil is sheared and compressed in the screw conveyor, and the soil will undergo shear dilatation or shear contraction when passing through the pores, leading to drastic changes in fluidity and potentially causing blockage problems.

[0096] When the void ratio of the tunnel boring machine (TBM) excavated soil is greater than the critical void ratio, it indicates that the soil tends to shrink during shearing, with particles rearranging more compactly and reducing volume. When the void ratio of the TBM excavated soil is less than the critical void ratio, the soil tends to dilate during shearing, with particles needing to climb over each other to move, resulting in increased volume. A void ratio deviation value can be obtained by measuring the difference between the actual void ratio and the critical void ratio. The specific actual void ratio of the excavated soil can be calculated by measuring the overall density and moisture content of the soil in real time. The overall density can be collected using a gamma-ray densitometer or microwave densitometer at the excavation port or the screw conveyor. The moisture content of the excavated soil can be estimated using a time-domain reflectometer or a resistivity / capacitance sensor, which will not be elaborated further here.

[0097] In practice, when the void ratio deviation is less than 0, it means that the tunnel boring machine excavated soil is sufficiently compacted during compression, leaving no extra space for particle movement. When the void ratio deviation is greater than or equal to 0, it means that the tunnel boring machine excavated soil has enough space for particle rearrangement and rolling during compression. Therefore, when both void ratio deviation and soil-water separation characterization factors are introduced, if it is found that... If the void ratio deviation is less than 0, then a higher level of soil and water condition early warning information can be output, such as extremely high risk; if it is found Furthermore, if the void ratio deviation is less than 0, the soil and water condition early warning information can be output as medium to high risk. Correspondingly, if it is found... Furthermore, if the porosity deviation is greater than 0, the water and soil condition early warning information can be output as medium to low risk. The specific coordination method will not be elaborated on here.

[0098] In a preferred embodiment, after obtaining the soil and water condition assessment result, in order to avoid the risk of blockage in the screw conveyor, it is also necessary to quickly activate the corresponding soil and water condition adjustment strategy. Therefore, after generating the corresponding soil and water condition early warning information based on the obtained soil and water condition assessment result, the method further includes:

[0099] Step A1: Obtain the warning content information presented by the soil and water status early warning information; the warning content information shall include at least: the soil and water status judgment result and the value of the soil and water separation characterization factor;

[0100] Step A2: Based on the water and soil status determination results and the values ​​of water and soil separation characterization factors, activate the corresponding water and soil status adjustment strategy.

[0101] Since the soil and water condition early warning information can display the current risk level of blockage, the corresponding soil and water condition adjustment strategy is only activated when the soil and water condition assessment result indicates that soil and water separation will occur or that there is a risk of soil and water separation. If the soil and water condition assessment result indicates that soil and water separation will not occur, the soil and water condition adjustment strategy is not activated. The soil and water condition adjustment strategy here mainly refers to measures that use the principle of foam injection to adjust the current soil and water condition of the shield tunneling excavation.

[0102] It should be noted that foam injection essentially involves introducing a large number of fine, stable air bubbles to fundamentally change the physical and mechanical properties and rheological characteristics of the slag, transforming it from an unstable, easily clogged solid particle aggregate into a uniform, stable, and impermeable plastic fluid.

[0103] Since the water and soil condition assessment results are different, the corresponding water and soil condition adjustment strategies are also different. Specifically, the process of activating the corresponding water and soil condition adjustment strategy based on the water and soil condition assessment results and the values ​​of the water and soil separation characterization factors is as follows: If the water and soil condition assessment result indicates that the shield tunneling excavated soil will experience water and soil separation, then the first water and soil condition adjustment strategy is activated; the first water and soil condition adjustment strategy is to inject foam into the shield tunneling excavated soil according to the first preset injection ratio; if the water and soil condition assessment result indicates that the shield tunneling excavated soil is at risk of water and soil separation, then the second water and soil condition adjustment strategy is activated; the second water and soil condition adjustment strategy is to inject foam into the shield tunneling excavated soil using a progressive injection mode.

[0104] Specifically, since the soil and water condition assessment indicates that the shield tunneling excavated soil will experience soil-water separation, it means that the current situation is at a high risk. Therefore, the foam ratio needs to be adjusted to its maximum extent to rapidly adjust the physical and mechanical properties and rheological characteristics of the shield tunneling excavated soil. The first soil and water condition adjustment strategy here can be understood as injecting foam into the shield tunneling excavated soil at a foam injection ratio of 5%, where 5% is the first preset injection ratio. Conversely, since the soil and water condition assessment indicates that the shield tunneling excavated soil is at risk of soil-water separation, it means that the current situation is at a medium risk. In this case, a gradual foam injection method can be adopted, meaning that the foam injection ratio adjustment range varies with the soil and water condition. The value increases and decreases linearly, thereby achieving fine control and avoiding excessive foam injection. For example, the second soil and water condition adjustment strategy adopts a gradual, small-amplitude (e.g., 2% to 5% per level) foam increase method.

[0105] It should be noted that, for both the first and second soil and water condition adjustment strategies, real-time data is used during the specific implementation phase. As a monitoring reference, only in real time... Foam injection can only be stopped when the value exceeds the second preset threshold to ensure that the shield tunneling excavation does not experience soil-water separation. Regarding the dynamic switching between the first and second soil-water state adjustment strategies, for example, when the first soil-water state adjustment strategy is used to adjust the shield tunneling excavation, it is found that the soil-water separation characteristic factor is already between the first and second preset thresholds (within the range where the shield tunneling excavation is at risk of soil-water separation), then the gradual mode of the second soil-water state adjustment strategy can be used to inject foam.

[0106] In this embodiment of the invention, different values ​​of water and soil separation characterization factors can correspond to different foam injection ratios. This depends on the previous calibration test. The test can yield an example of the foam ratio injection reference table structure shown in Table 2 below. Finally, the actual values ​​of water and soil separation characterization factors can be found according to the foam ratio injection reference table to confirm the corresponding foam injection ratio.

[0107] Table 2. Example of Foam Ratio Injection Reference Table Structure

[0108]

[0109] Based on the above description, this invention proposes a method for preventing soil blockage in earth pressure balance tunnel boring machines (TBMs). This method first measures the permeability coefficient and lateral compression modulus of the TBM muck, and calculates the consolidation coefficient of the muck. Then, based on the excavation radius of the TBM tunnel, the radius of the screw conveyor, the tunneling speed, and the loosening coefficient of the muck, it calculates the characteristic velocity of the muck in the screw conveyor. Furthermore, it calculates the water-soil separation characterization factor of the muck in the screw conveyor using the consolidation coefficient and characteristic velocity, and evaluates the blockage risk of the muck in the screw conveyor based on the water-soil separation characterization factor. Finally, it mitigates the muck blockage risk by progressively increasing the foam injection ratio. This method provides a scientific theoretical basis for preventing muck blockage in earth pressure balance TBMs, greatly reducing the risk of muck blockage in the screw conveyor and ensuring the safe and efficient tunneling of the TBM.

[0110] The above text combined Figures 1-2 This invention provides a detailed description of a method for preventing soil blockage through earth pressure balance, as illustrated in the appendix. Figure 3 The prevention system 600 provided in the embodiments of the present invention will be described.

[0111] Specifically, an earth pressure balance slag blockage prevention system according to an embodiment of the present invention includes:

[0112] The acquisition module 601 is used to identify the tunneling area based on the shield tunneling site information, and to acquire the permeability coefficient, lateral compression modulus and density of the shield excavated soil in the current tunneling area.

[0113] Calculation module 602 is used to calculate the consolidation coefficient of the shield tunneling muck in the screw conveyor based on the permeability coefficient, the lateral compression modulus and the muck density.

[0114] In addition, the calculation module 602 is also used to obtain the construction characteristic parameters of the tunneling area, and calculate the water and soil separation characterization factor of the shield tunneling excavation based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operation parameters;

[0115] The early warning module 603 is used to output the water and soil status determination result of the shield tunneling muck based on the water and soil separation characterization factor, and generate corresponding water and soil status early warning information based on the water and soil status determination result.

[0116] The prevention system 600 according to an embodiment of the present invention may correspond to performing the method described in the embodiment of the present invention, and the above and other operations and / or functions of each module of the prevention system 600 are respectively for implementing Figure 1 The corresponding process of the method in the illustrated embodiment will not be described in detail here for the sake of brevity.

[0117] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A method for preventing soil blockage due to earth pressure balance, characterized in that, include: Based on the information of the shield tunneling site, the tunneling area is identified, and the permeability coefficient, lateral compression modulus, and density of the shield excavated soil in the current tunneling area are obtained. Based on the permeability coefficient, lateral compression modulus, and soil density, the consolidation coefficient of the shield tunneling excavated soil in the screw conveyor is calculated. The construction characteristic parameters of the tunneling area are obtained, and the water-soil separation characterization factor of the shield tunnel excavation soil is calculated based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operating parameters; Based on the water and soil separation characterization factors, the water and soil status determination results of the shield tunnel slag are output, and based on the water and soil status determination results, corresponding water and soil status early warning information is generated. Based on the shield tunneling site information, the tunneling area is identified, and the permeability coefficient, lateral compression modulus, and density of the shield excavated soil within the current tunneling area are obtained, including: Obtain the shield tunneling site information and confirm the tunneling area based on the shield tunneling site information; the shield tunneling site information includes at least: the area code of each tunneling area; Obtain the area code of the current tunneling area, and based on the area code, call the shield excavation feature calibration database to obtain the permeability coefficient, lateral compression modulus and excavation density of the shield excavation in the current tunneling area; The shield tunneling excavation soil characteristic calibration database is established by conducting permeability and compression tests on each shield tunneling excavation soil sample; the shield tunneling excavation soil characteristic calibration database includes at least: different regional codes and the permeability coefficient, lateral compression modulus, and soil density of the shield tunneling excavation soil corresponding to each regional code.

2. The method for preventing soil blockage due to earth pressure balance as described in claim 1, characterized in that, The construction characteristic parameters of the tunneling area are obtained, and the water-soil separation characterization factor of the shield tunneling excavation is calculated based on the construction characteristic parameters and the consolidation coefficient, including: The construction parameters and equipment operating parameters are obtained; the construction parameters include: the excavation radius of the shield tunnel and the soil loosening coefficient; the equipment operating parameters include: the radius of the screw conveyor and the tunneling speed of the shield machine. Based on the excavation radius, the loosening coefficient of the stratum, the radius of the screw conveyor, and the tunneling speed of the tunnel boring machine, the characteristic velocity of the tunnel excavation material in the screw conveyor is calculated. Based on the characteristic velocity, consolidation coefficient, and screw conveyor radius, the water-soil separation characterization factor of the shield tunnel excavation soil is calculated.

3. The method for preventing soil blockage due to earth pressure balance as described in claim 1, characterized in that, Based on the water and soil separation characterization factors, the water and soil state determination result of the shield tunneling excavated soil is output, and based on the water and soil state determination result, corresponding water and soil state early warning information is generated, including: Obtain the water-soil separation characterization factors; If the water and soil separation characterization factor is less than the first preset threshold, the water and soil state determination result is that the shield tunneling slag will undergo water and soil separation. If the water and soil separation characterization factor is greater than or equal to the first preset threshold and less than or equal to the second preset threshold, then the water and soil status determination result is that the shield tunneling slag is at risk of water and soil separation. If the water and soil separation characterization factor is greater than the second preset threshold, then the water and soil state determination result is that the shield tunneling slag will not undergo water and soil separation. Based on the obtained water and soil condition assessment results, corresponding water and soil condition early warning information is generated.

4. The method for preventing soil blockage due to earth pressure balance as described in claim 3, characterized in that, After generating corresponding soil and water condition early warning information based on the obtained soil and water condition assessment results, the process also includes: Obtain the warning content information presented by the water and soil condition warning information; the warning content information includes at least: the water and soil condition determination result and the value of the water and soil separation characterization factor; Based on the water and soil condition determination results and the values ​​of the water and soil separation characterization factors, the corresponding water and soil condition adjustment strategy is activated.

5. The method for preventing soil blockage due to earth pressure balance as described in claim 4, characterized in that, Based on the soil and water condition assessment results and the values ​​of soil and water separation characterization factors, the corresponding soil and water condition adjustment strategies are activated, including: If the soil and water condition determination result indicates that soil and water separation will occur in the shield tunnel excavation, then the first soil and water condition adjustment strategy is activated; the first soil and water condition adjustment strategy is to inject foam into the shield tunnel excavation according to the first preset injection ratio. If the soil and water condition determination result indicates that there is a risk of soil-water separation in the shield tunnel excavation soil, then the second soil and water condition adjustment strategy is activated; the second soil and water condition adjustment strategy is to inject foam into the shield tunnel excavation soil using a gradual injection mode.

6. The method for preventing soil blockage due to earth pressure balance as described in claim 1, characterized in that, When conducting permeability and compression tests on the tunnel boring machine (TBM) excavated soil samples, the pressure environment in the permeability and compression tests is consistent with that of the TBM construction site.

7. An earth pressure balance slag blockage prevention system, characterized in that, include: The acquisition module is used to identify the tunneling area based on the shield tunneling site information, and to acquire the permeability coefficient, lateral compression modulus and density of the shield excavated soil in the current tunneling area. The calculation module is used to calculate the consolidation coefficient of the shield tunneling excavated soil in the screw conveyor based on the permeability coefficient, the lateral compression modulus, and the soil density. Furthermore, the calculation module is also used to obtain the construction characteristic parameters of the tunneling area, and to calculate the water and soil separation characterization factor of the shield tunnel excavation based on the construction characteristic parameters and the consolidation coefficient; the construction characteristic parameters include at least: construction parameters and equipment operating parameters; The early warning module is used to output the water and soil status determination result of the shield tunneling debris based on the water and soil separation characterization factor, and generate corresponding water and soil status early warning information based on the water and soil status determination result. The acquisition module is also used to acquire the shield tunneling site information, confirm the tunneling area based on the shield tunneling site information, acquire the area code of the current tunneling area, and, based on the area code, call the shield excavation soil feature calibration database to obtain the permeability coefficient, lateral compression modulus, and excavation soil density of the shield excavation soil in the current tunneling area; the shield tunneling site information includes at least: the area code of each tunneling area; The shield tunneling excavation soil characteristic calibration database is established by conducting permeability and compression tests on each shield tunneling excavation soil sample; the shield tunneling excavation soil characteristic calibration database includes at least: different regional codes and the permeability coefficient, lateral compression modulus, and soil density of the shield tunneling excavation soil corresponding to each regional code.

Images