A construction method for controlling uplift based on dewatering of foundation pits on both sides of a subway

Abstract

The present invention relates to the technical field of subway bilateral expansion construction, and in particular to a construction method for controlling uplift based on dewatering of foundation pits on both sides of the subway. The method includes performing finite element simulation on the excavation plan to determine the uplift amount of the subway. In response to the uplift amount exceeding the standard, pumping and drainage of the confined aquifer are carried out simultaneously on both sides of the subway. During the pumping and drainage process, according to the difference between the respective pumping and drainage speeds of both sides of the subway in the current cycle and the target pumping and drainage speed, the surcharge strategy above both sides of the subway in the next cycle is determined to balance the differential uplift caused by the pumping and drainage speed fluctuations. After the uplift is controlled, pumping or recharge is carried out through the water level control wells around the station and the tunnel to keep the water head heights of the first confined aquifer and the second confined aquifer in the confined observation wells constant. By means of the adaptive combination of groundwater pumping and recharge and surcharge in the time sequence level, the phenomena of subway subsidence and differential deformation occurring in the process of subway bilateral expansion construction in the prior art are effectively alleviated.

Description

Technical Field

[0001] The present invention relates to the technical field of subway bilateral expansion construction, and particularly relates to a construction method for controlling uplift based on dewatering of foundation pits on both sides of the subway. Background Art

[0002] At present, the construction of urban high-rise buildings and the scale of subway mileage are continuously expanding, and the foundation pits of high-rise buildings and urban subway stations are developing in a larger and deeper direction. During the construction of foundation pit projects near the subway, the settlement and uplift deformation of the subway will be caused by the unloading of earth excavation and dewatering, which will affect the operation safety of the subway. The reason is that the stress environment of the strata around the foundation pit changes due to the influence of the excavation unloading effect, and phenomena such as surface settlement and bottom heave deformation become more serious as the excavation depth of the foundation pit increases. In particular, when the foundation pit excavation is located in relatively soft strata, due to the low strength of the strata soil or the influence of strong groundwater factors, the soil on the side of the foundation pit is extremely likely to produce a certain range of deformation and the deformation degree is generally large. Therefore, during the construction of the foundation pit, not only the settlement and uplift deformation of the subway need to be controlled, but also the differential deformation of the subway tunnel needs to be controlled. Along the direction of the foundation pit, due to the different degrees of influence of excavation unloading and dewatering, the subway will produce different deformations, and there is a large difference in the deformation of the subway between the excavated area and the non-excavated area of the foundation pit. In addition, at the intersection of the subway station body and the tunnel, due to the different structural stiffnesses on both sides and the different abilities to resist deformation after excavation unloading and dewatering, excessive differential deformation will also be caused. Excessive differential deformation will cause the opening of cracks in the subway tunnel, resulting in tunnel water seepage, causing track deformation and reducing the comfort of the operating subway, seriously affecting the operation safety of the subway. Summary of the Invention

[0003] The purpose of the present invention is to provide a construction method for controlling uplift based on dewatering of foundation pits on both sides of the subway, so as to effectively alleviate the phenomena of subway settlement and uplift and differential deformation that occur in the process of subway bilateral expansion construction in the prior art.

[0004] The present invention provides a construction method for controlling uplift based on dewatering of foundation pits on both sides of the subway. The construction method for controlling uplift based on dewatering of foundation pits on both sides of the subway includes:

[0005] Step S1, perform finite element simulation on the excavation schemes on both sides of the subway, and determine the uplift amount of the subway based on the finite element simulation results;

[0006] Step S2, in response to the uplift amount of the subway exceeding the standard, determine to simultaneously drain the confined aquifer on both sides of the subway;

[0007] Step S3: At the start of pumping and drainage, give priority to pumping and draining the first confined aquifer. If the pumping and drainage volume of the first confined aquifer reaches the first limit value and the heave is still not controlled, pump and drain the first confined aquifer and the second confined aquifer simultaneously; if the pumping and drainage volume of the first confined aquifer reaches the second limit value and the heave is still not controlled, only pump and drain the second confined aquifer.

[0008] Step S4: During the pumping and drainage process, determine the surcharge strategy above both sides of the subway in the next cycle according to the difference between the respective pumping and drainage speeds of both sides of the subway and the target pumping and drainage speed in the current cycle, so as to balance the differential heave caused by the pumping and drainage speed fluctuations.

[0009] Step S5: After the heave is controlled, pump and drain or recharge through the water level control wells around the station and the tunnel to keep the water head heights of the first confined aquifer and the second confined aquifer in the pressure observation wells constant.

[0010] Wherein, the first limit value is less than the second limit value, and the first confined aquifer is located above the second confined aquifer.

[0011] As a preferred technical solution of the construction method for controlling heave based on the dewatering of the foundation pits on both sides of the subway, during the process of pumping and draining the confined aquifers on both sides of the subway simultaneously, the target pumping and drainage speeds on both sides of the subway are the same.

[0012] As a preferred technical solution of the construction method for controlling heave based on the dewatering of the foundation pits on both sides of the subway, a plurality of water level control wells are arranged along the periphery of the station and the tunnel.

[0013] As a preferred technical solution of the construction method for controlling heave based on the dewatering of the foundation pits on both sides of the subway, obtain the pumping and drainage volume of each water level control well per unit time to determine the respective pumping and drainage speeds on both sides of the subway.

[0014] As a preferred technical solution of the construction method for controlling heave based on the dewatering of the foundation pits on both sides of the subway, the determination of the surcharge strategy above both sides of the subway in the next cycle according to the difference between the respective pumping and drainage speeds of both sides of the subway and the target pumping and drainage speed in the current cycle includes

[0015] In response to the existence of a difference between the pumping and drainage speed and the target pumping and drainage speed, determine the surcharge side above both sides of the subway in the next cycle according to the respective pumping and drainage speeds of both sides of the subway;

[0016] Wherein, the surcharge side is the side with the higher pumping and drainage speed among both sides of the subway.

[0017] As a preferred technical solution of the construction method for controlling heave based on the dewatering of the foundation pits on both sides of the subway, after the surcharge side is determined, it further includes:

[0018] Determine the total stacking capacity based on the difference in extraction speeds on both sides;

[0019] The total stacking capacity is positively correlated with the difference in pumping speed on both sides of the subway.

[0020] As a preferred technical solution for the construction method of controlling uplift based on dewatering of the foundation pits on both sides of the subway, after the pile load is determined, it also includes:

[0021] Get the target pumping volume for the next cycle.

[0022] The target pumping volume is evenly divided into a number of sub-target pumping volumes according to the number of times the heap load is applied;

[0023] After reaching any sub-target drainage volume, a load is applied once, and the single load volume is equal to the ratio of the total load volume to the number of applications.

[0024] As a preferred technical solution for the construction method of uplift control based on the dewatering of the foundation pits on both sides of the subway, the process of simultaneously pumping out the first confined aquifer and the second confined aquifer specifically includes:

[0025] Determine the hydraulic head height of each confined aquifer through confined observation wells;

[0026] The pumping rate of each water layer is dynamically adjusted to ensure that the water head heights of the first confined aquifer and the second confined aquifer are higher than the corresponding threshold value while meeting the target pumping rate and the difference between the water head heights of the first confined aquifer and the second confined aquifer is constant.

[0027] As a preferred technical solution for the construction method of uplift control based on dewatering of foundation pits on both sides of the subway, the determination of the loading strategy above both sides of the subway in the next cycle also includes determining the loading position, which is located in the loading area and close to the water level control well with the smallest pumping speed on the corresponding side.

[0028] The beneficial effects of the present invention are:

[0029] The present invention dynamically combines the pumping of the confined aquifer and the back pressure control technology of the back loading, couples the settlement caused by the pumping of the groundwater with the uplift caused by the unloading of the earthwork excavation, dynamically controls the height of the confined water head within a reasonable range, couples the uplift of the excavation in the corresponding area, and controls the height of the confined water head of the first and second layers, couples the differential settlement and deformation of the subway station and the tunnel, and resists the influence of the uneven release of the excavation stress inside the foundation pit. After the uplift is controlled, the confined water head height of the station and the tunnel is kept stable and does not drop by recharging each aquifer under pressure. Actively pumping the confined water produces a slight settlement at the junction, balances the buoyancy of the subway, and effectively improves the uplift control effect of the subway station and the tunnel.

[0030] In particular, the present invention analyzes the pumping and drainage speed differences on both sides of the subway, and determines the surcharge strategy to couple the settlement control differences caused by the pumping and drainage speed differences, further avoiding differential settlement deformation of the subway station, tunnel and surrounding soil mass, and further improving the uplift control effect on the subway station and tunnel.

[0031] In particular, the present invention has a connection logic for pumping and draining corresponding aquifers in stages. While ensuring the structural stability of relevant areas of each confined aquifer, the pumping and drainage process makes the control of uplift tend to be stable, avoiding the reduction of structural stability caused by single-layer pumping and drainage with too fast single-layer change or lack of analysis, and further improving the uplift control effect on the subway station and tunnel. Brief Description of the Drawings

[0032] Figure 1 It is a flow chart of the construction method for uplift control based on foundation pit dewatering on both sides of the subway in the embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of the distribution of water level control wells in the embodiment of the present invention Figure 1 ;

[0034] Figure 3 It is a schematic diagram of the distribution of water level control wells in the embodiment of the present invention Figure 2 ;

[0035] Figure 4 It is a flow chart for determining the surcharge timing in the embodiment of the present invention.

[0036] In the figure: 1. Subway station; 2. Subway tunnel; 3. Water level control well; 4. Confined observation well; 5. Water level control well for the first confined aquifer; 6. Water level control well for the second confined aquifer; 7. Confined observation well for the first confined aquifer; 8. Confined observation well for the second confined aquifer; 9. First confined aquifer; 10. Second confined aquifer. Detailed Embodiments

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions. Moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and diagonally above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under" and "beneath" the second feature includes the first feature being directly below and diagonally below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0039] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements.

[0040] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0042] For a better understanding of the present invention, the following is an introduction and interpretation of the construction scenario and terms:

[0043] Confined aquifer: The geological layer where the confined water is located is called the confined aquifer, which is the water in the aquifer filled between the upper and lower confining layers. It is under pressure. When the overlying confining layer is drilled through, the water can rise or gush out from the borehole. There are generally multiple confined aquifers. Considering the construction difficulty, only the first two confined aquifers closest to the ground surface (i.e., the first confined aquifer and the second confined aquifer) are used in this embodiment.

[0044] Confined observation well, also known as the confined water level observation well, can determine the water pressure of the confined aquifer by observing the water level of the confined observation well;

[0045] The water head height, i.e., the water pressure height: the vertical height difference generated by gravity or pressure factors when the fluid is in a static or dynamic state.

[0046] Based on the above definitions, as Figure 1 shown, this embodiment provides a construction method for controlling uplift based on the dewatering of foundation pits on both sides of the subway, including:

[0047] Step S1, perform a finite element simulation on the excavation schemes on both sides of the subway, and determine the uplift amount of the subway based on the finite element simulation results;

[0048] Specifically, before performing the finite element simulation in this embodiment, the construction of the finite element model is preferentially carried out. First, determine the horizontal and vertical ranges of the model. In this embodiment, the model covers the full width of the foundation pit and the influence area of at least 2 times the width of the foundation pit on each side outside the foundation pit to ensure that the influence of the formation boundary conditions on the simulation results can be ignored. The model extends vertically downward from the ground surface to 1.5 times the depth of the foundation pit below the bottom of the foundation pit excavation to ensure the coverage of each geological layer. The model is constructed using three-dimensional finite element units, and the model units are divided into: formation units, foundation pit retaining structure units, beam units, and / or shell units. The formation units use solid units to simulate the mechanical properties of the strata around the foundation pit (the strata simulated in this embodiment include plain fill, cohesive soil, silty sand, confined aquifer, and bedrock). The foundation pit retaining structure units use plate and shell units to simulate the foundation pit support structure. The structures simulated in this embodiment include diaphragm walls and row pile structures. The beam units and / or shell units are used to simulate the tunnel lining, and the parameters include the elastic modulus, stiffness, and structural dimensions of the tunnel material.

[0049] Furthermore, fixed support boundaries are respectively set at the horizontal edges of the model to constrain the horizontal displacement. A fixed support is applied at the bottom of the model to constrain the vertical displacement. A seepage boundary condition is set in the confined aquifer area to simulate the natural flow and pumping effect of groundwater. After setting the boundary conditions, an initial in-situ stress field is applied through the formation distribution and historical sedimentation process to ensure that the initial state of the model truly reflects the natural formation environment. Simulate the step-by-step unloading of the foundation pit excavation, and gradually remove the soil load in the foundation pit area. Simulate the process of applying the staged surcharge load in the surcharge area. Set the initial water head of the confined aquifer to simulate the influence of the water head change during the pumping process on the formation stress and deformation. The finite element model is obtained through the above steps;

[0050] After the model is established, the stress distribution of the formation in the natural state is obtained through static analysis to ensure the stability of the simulated initial conditions. Apply the excavation unloading effect corresponding to the excavation scheme to the model in stages to determine the uplift amount of the subway caused by the foundation pit scheme.

[0051] Step S2, in response to the heave amount of the subway exceeding the standard, it is determined that the pumping and drainage of the confined aquifer are carried out simultaneously on both sides of the subway; specifically, the standard value of the heave amount is determined according to the construction standards and requirements. Carrying out simultaneously on both sides of the subway (i.e., on both sides of the tunnel and the subway station) can avoid the short-term difference in the water head height distribution caused by unilateral pumping and drainage. Furthermore, it will cause uneven distribution of soil stress and affect the construction quality. For the pumping and drainage of the confined aquifer, in this embodiment, a plurality of water level control wells are set at the pre-determined drainable positions along the periphery of the subway and the tunnel. Some water level control wells are connected to the first confined aquifer, and some water level control wells are connected to the second confined aquifer. Please refer to Figure 2 and Figure 3 As shown, the water level control wells of this embodiment are distributed on both sides of the subway station 1 and the subway tunnel 2 as shown in Figure 3 The water head heights of the first confined aquifer 9 and the second confined aquifer 10 are determined by the confined observation wells 4 on the outside. The heave of the subway station 1 and the subway tunnel 2 is controlled by pumping and draining several inner water level control wells 3. For the first confined aquifer 9 and the second confined aquifer 10, the first confined aquifer water level control wells 5 and the second confined aquifer water level control wells 6 with different depths are set respectively, as well as the first confined aquifer confined observation wells 7 and the second confined aquifer confined observation wells 8 with different depths. In this way, through the connection logic of pumping and draining the corresponding aquifers in stages, while ensuring the structural stability of the relevant areas of each confined aquifer, the control of the heave during the pumping and draining process tends to be stable, avoiding the reduction of structural stability caused by the single-layer pumping and draining with too fast single-layer change or lack of analysis, and further improving the control effect of the heave of the subway station and the tunnel.

[0052] Step S3, at the start of pumping and draining, the pumping and draining of the first confined aquifer are carried out preferentially. If the pumping and drainage volume of the first confined aquifer reaches the first limit value and the heave is still not controlled, the first confined aquifer and the second confined aquifer are pumped and drained simultaneously; if the pumping and drainage volume of the first confined aquifer reaches the second limit value and the heave is still not controlled, only the second confined aquifer is pumped and drained; specifically, in this embodiment, considering that the depth of the first confined aquifer is smaller and the construction difficulty is lower, preferentially carrying out the pumping and draining of the first confined aquifer under the premise of ensuring the balance of the interlayer pressure can effectively improve the control effect of the heave. When the balance of the interlayer pressure is about to be affected (i.e., reaching the first limit value), the second confined aquifer is pumped and drained synchronously to keep the pressure distribution between the layers in a stable state. Specifically:

[0053] The water head heights of each confined aquifer are determined through the confined observation wells;

[0054] Adjust the pumping and drainage volume of each confined aquifer so that the water head heights of the first confined aquifer and the second confined aquifer are higher than the corresponding thresholds while meeting the target pumping and drainage volume, and the difference between the water head heights of the first confined aquifer and the second confined aquifer is constant.

[0055] Moreover, there should be an upper limit to the pumping and drainage volume of the first confined aquifer. After reaching the upper limit, it will affect the overall structural strength. When reaching this upper limit (i.e., the second limit value), only the pumping and drainage of the second confined aquifer are carried out until the uplift is controlled or the pumping and drainage volume of the second confined aquifer reaches the upper limit. It should be understood that in this embodiment, the uplift being controlled means that the uplift speed of the subway begins to decrease. For the first limit value and the second limit value, they need to be determined in combination with the actual scenario and the elevation coverage ranges of the first confined aquifer and the second confined aquifer, as long as the determination purpose of this embodiment is satisfied, which will not be elaborated here.

[0056] Step S4, during the pumping and drainage process, according to the difference between the respective pumping and drainage speeds on both sides of the subway within the current period and the target pumping and drainage speed, determine the surcharge strategy above both sides of the subway in the next period to balance the differential uplift caused by the pumping and drainage speed fluctuations. If there is no difference in the pumping and drainage speeds on both sides, no surcharge is applied and only pumping and drainage are used to control the uplift.

[0057] The surcharge strategy specifically includes the surcharge side, the surcharge amount on the surcharge side, the surcharge timing, and the surcharge position.

[0058] The determination of the surcharge side includes: obtaining the pumping and drainage volume of each water level control well per unit time to determine the pumping and drainage speed of each water level control well, determining the average pumping and drainage speed of each water level control well on one side as the pumping and drainage speed of that side, comparing the pumping and drainage speeds on both sides, and taking the side with the higher pumping and drainage speed among the two sides of the subway as the surcharge side.

[0059] The determination of the total surcharge amount includes: The determination of the total surcharge amount is based on the historical pumping and drainage and uplift relationship model and real-time monitoring data. First, by collecting historical construction data, including the pumping and drainage speed of the water level control well and the uplift amount on both sides of the subway, establish a fitting relationship model between the pumping and drainage speed difference and the uplift difference. The fitting relationship model in this embodiment is a linear model. In implementation, for complex geology, it can be further constructed as other models, which are all existing technologies. Exemplarily, the linear model in this embodiment is to determine the uplift difference amount ΔH(t):

[0060] ,

[0061] where k is the formation response coefficient (obtained by linear regression based on the above historical construction data, and the dimension of k satisfies that the output value is in the unit of distance), ΔV(t) is the difference amount of the pumping and drainage speeds on both sides within the unit time t (the difference amounts are all positive values), and b is the initial bias of the uplift difference.

[0062] Based on the real-time uplift difference, select the surcharge corresponding to the above-mentioned uplift difference ΔH(t) according to empirical data. The side for surcharge is selected based on the side with a higher pumping rate, and the surcharge position is preferably set at the surchargeable position near the water level control well with the minimum pumping rate.

[0063] Furthermore, the determination of the surcharge timing includes:

[0064] Step S41: Obtain the target pumping volume for the next cycle.

[0065] Step S42: Evenly divide the target pumping volume into several sub-target pumping volumes according to the number of surcharge applications.

[0066] Step S43: Apply a surcharge once after reaching any sub-target pumping volume. The single surcharge volume is equal to the ratio of the total surcharge volume to the number of applications. On the premise of the existence of pumping rate differences, the uplift difference can be effectively controlled through the staged synchronization of surcharge and pumping, improving the uplift control effect.

[0067] Specifically, for the surcharge above both sides of the subway, it can effectively control the development of the maximum vertical deformation point. Before the surcharge implementation, check the subway structure design parameters and review the design load requirements for the upper part of the tunnel. Through the combination of water injection, medium sand, and steel profiles, the corresponding single surcharge volume is achieved. By determining the surcharge strategy and coupling the uplift control difference caused by the pumping rate difference, the differential settlement deformation of the subway station, tunnel, and surrounding soil is further avoided, and the uplift control effect for the subway station and tunnel is further improved.

[0068] Step S5: After the uplift is controlled, pump or recharge through the water level control wells around the station and tunnel to keep the water head heights of the first and second confined aquifers in the confined observation wells constant; in this way, the stability of the soil and the confined aquifer during subsequent construction can be effectively improved.

[0069] In the above embodiment, through the dynamic combination of confined aquifer pumping and surcharge backpressure control technology, the settlement amount generated by groundwater pumping is coupled with the uplift amount generated by soil excavation unloading, dynamically controlling the confined water head height within a reasonable range, coupling the excavation uplift in the corresponding area, and coupling the differential settlement deformation of the subway station and tunnel by controlling the water head heights of the first and second layers, resisting the influence of uneven excavation stress release inside the foundation pit. After the uplift is controlled, each aquifer is pressure-recharged to keep the confined water head height within the station and tunnel ranges stable without dropping. Actively pumping the confined water generates a small amount of settlement at the connection position to balance the subway floating, effectively improving the uplift control effect for the subway station and tunnel.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A construction method for uplift control based on dewatering of foundation pits on both sides of a subway, characterized in that: include: Step S1, performing finite element simulation on the excavation scheme on both sides of the subway, and determining the uplift amount of the subway based on the finite element simulation results; Step S2, in response to the uplift amount of the subway exceeding the standard, determining to simultaneously pump out the confined aquifer on both sides of the subway; Step S3, when the pumping starts, the first confined aquifer is pumped first. If the pumping amount of the first confined aquifer reaches the first limit and the uplift is still not controlled, the first confined aquifer and the second confined aquifer are pumped simultaneously; if the pumping amount of the first confined aquifer reaches the second limit and the uplift is still not controlled, only the second confined aquifer is pumped; Step S4, during the pumping process, the stacking strategy on both sides of the subway in the next cycle is determined according to the difference between the respective pumping speeds on both sides of the subway in the current cycle and the target pumping speed, so as to balance the differential uplift caused by the fluctuation of the pumping speed; The determination of the loading strategy specifically includes: in response to the difference between the pumping speed and the target pumping speed, determining the loading side above the two sides of the subway in the next cycle according to the respective pumping speeds of the two sides of the subway; and, after the stacking side is determined, determining the total stacking capacity on the stacking side in the next cycle according to the difference in pumping speeds on both sides; Step S5, after the uplift is controlled, the water head height of the first confined aquifer and the second confined aquifer in the confined observation well is kept constant by pumping or recharging the water level control wells around the station and the tunnel; Among them, the first limit value is smaller than the second limit value, the first confined aquifer is located above the second confined aquifer, and the loading side is the side with higher pumping speed on both sides of the subway; the total loading capacity is positively correlated with the absolute value of the difference in pumping speed on both sides of the subway.

2. The construction method for uplift control based on dewatering of foundation pits on both sides of the subway according to claim 1 is characterized in that: In the process of simultaneously pumping out the confined aquifer on both sides of the subway, the target pumping speed on both sides of the subway is the same.

3. The construction method for uplift control based on dewatering of foundation pits on both sides of the subway according to claim 2 is characterized in that: The water level control wells are arranged along the periphery of the station and the tunnel, and there are at least three water level control wells.

4. The construction method for uplift control based on dewatering of foundation pits on both sides of a subway according to claim 3 is characterized in that: The step S4 comprises: The pumping volume of each water level control well per unit time is obtained to determine the pumping speed on both sides of the subway.

5. The construction method for uplift control based on dewatering of foundation pits on both sides of a subway according to claim 4 is characterized in that: After the total heap load is determined, the method further includes: Obtain the target extraction volume for the next cycle; The target pumping volume is evenly divided into a number of sub-target pumping volumes according to the number of times the heap load is applied; After reaching any sub-target drainage volume, a load is applied once, and the single load volume is equal to the ratio of the total load volume to the number of applications.

6. The construction method for uplift control based on dewatering of foundation pits on both sides of a subway according to claim 5 is characterized in that: The process of simultaneously pumping out the first confined aquifer and the second confined aquifer specifically includes: Determine the hydraulic head height of each confined aquifer through confined observation wells; The pumping rate of each confined aquifer is adjusted so that the water head heights of the first confined aquifer and the second confined aquifer are higher than the corresponding threshold value while meeting the target pumping rate and the difference between the water head heights of the first confined aquifer and the second confined aquifer is constant.

7. The construction method for uplift control based on dewatering of foundation pits on both sides of a subway according to claim 6 is characterized in that: The method of determining the loading strategy for the next cycle above both sides of the subway also includes determining a loading position, which is located in the loading area and close to the water level control well with the smallest pumping speed on the corresponding side.

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