Foundation pit dewatering well arrangement optimization method and processing terminal

Abstract

The invention discloses a foundation pit dewatering well arrangement optimization method which is characterized by comprising the following steps: step 1, setting assumed conditions of a foundation pit dewatering seepage analysis model; step 2, based on the assumed conditions, establishing a numerical model for the foundation pit precipitation seepage analysis model to obtain a foundation pit precipitation seepage analysis numerical model; 3, setting a target function; 4, the target function serves as a constraint condition, iteration is conducted on the foundation pit precipitation seepage analysis numerical model, and the optimal solution of iteration serves as a final precipitation well design optimization result which comprises the number and the position of precipitation wells and the depth corresponding to each precipitation well. According to the foundation pit dewatering well optimization method, the obtained foundation pit dewatering well optimization result can better meet the actual requirements for the number, position and depth of the dewatering wells, the dewatering well arrangement is better matched with the requirements, waste is avoided, and the economical, energy-saving and environment-friendly effects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit dewatering in underground construction, and specifically to an optimization method for the layout of foundation pit dewatering wells and a processing terminal. Background Art

[0002] In the construction of foundation pit projects under some conditions of high groundwater level and rich water content in the formation, due to the requirements of the construction operation environment for foundation pit excavation and the significant impact of groundwater seepage on foundation pit excavation and support facilities. If the groundwater problem cannot be handled in a timely manner, it may lead to different degrees of settlement deformation of the soil mass in the foundation pit area and the surrounding building structures, and in severe cases, it may even cause huge economic losses and engineering safety accidents. Therefore, it is necessary to dewater the foundation pit. Foundation pit dewatering treatment is a key link in the design of foundation pit projects, and studying the optimization of foundation pit dewatering has important practical engineering significance.

[0003] For foundation pit dewatering, the existing treatment methods generally include open ditch drainage, light well point, multi-stage light well point, jet well point, sand (gravel) infiltration well, electro-osmosis well point, pipe well (deep well) dewatering, etc. In these treatment methods, foundation pit dewatering wells for dewatering are involved. Therefore, it is necessary to design and optimize the layout of foundation pit dewatering wells, including the number and layout position of the dewatering wells.

[0004] The existing design optimization methods for foundation pit dewatering wells generally calculate the total water inflow of the foundation pit using the "large well method" according to the specifications first, and then calculate the maximum water output of a single foundation pit dewatering well based on the parameters of the foundation pit dewatering well filter and the aquifer parameters. The number of foundation pit dewatering wells is determined by the total water inflow of the foundation pit dewatering wells and the maximum water output of a single foundation pit dewatering well, and the position of the dewatering wells is set in a uniform distribution manner. Such a design optimization method for foundation pit dewatering wells only uses the direct average well flow rate (total water inflow of the foundation pit dewatering wells / maximum water output of a single foundation pit dewatering well), and the layout position of its dewatering wells has little or no basis, does not consider the reasonable number of dewatering wells, and even less considers the influence of the position, depth, and flow rate of the dewatering wells. The number of dewatering wells does not match the required precipitation, resulting in a large error in the number of dewatering wells, not only causing high construction costs but also wasting resources.

[0005] Therefore, a more refined and flexible design method for the number, position, depth, and flow rate of dewatering wells is needed to achieve the effects of economy, energy conservation, and environmental protection. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an optimization method for the layout of foundation pit dewatering wells and a processing terminal, which can solve the problems described in the background art.

[0007] The technical solution for achieving the object of the present invention is as follows: An optimization method for the layout of foundation pit dewatering wells, comprising the following steps:

[0008] Step 1: Set the assumption conditions of the foundation pit dewatering seepage analysis model. The assumption conditions characterize the parameters of the foundation pit dewatering seepage analysis model, and the foundation pit dewatering seepage analysis model is used to analyze the water seepage condition of the foundation pit dewatering wells;

[0009] Step 2: Based on the assumption conditions, establish a numerical model for the foundation pit dewatering seepage analysis model to obtain the numerical model of the foundation pit dewatering seepage analysis;

[0010] Step 3: Set the following objective function Obj:

[0011]

[0012] In the above formula, t represents time, t i represents the set dewatering time, h i ≤h s , represents that after the dewatering time t i , the water level elevation at any point within the dewatering target area Z is less than or equal to the dewatering target water level elevation, min(n) represents the minimum number of dewatering wells n, and min(Q) represents the minimum water inflow Q.

[0013] The above objective function Obj means that after the dewatering time t i , it satisfies that the water level elevation at any point within the target area Z is less than or equal to the dewatering target water level elevation, and the minimum water inflow under the minimum number of dewatering wells is used as the solution target;

[0014] Step 4: Using the above objective function Obj as a constraint condition, iterate the numerical model of the foundation pit dewatering seepage analysis, and the optimal solution of the iteration is used as the final optimization result of the dewatering well design, including the number of dewatering wells, positions, and the depths corresponding to each dewatering well.

[0015] Further, in Step 1, the assumption conditions include:

[0016] (1) The simulated seepage layer of the foundation pit dewatering seepage analysis model is a finite phreatic aquifer with constant head lateral recharge and no vertical recharge. The aquifer is homogeneous and isotropic. Before dewatering, the initial water head of the aquifer is horizontal. The impervious bottom plate of the foundation pit dewatering well is horizontal. The water level and flow rate of a single foundation pit dewatering well both conform to the steady well flow model of Dupuit, and the dewatering of the group wells composed of all foundation pit dewatering wells conforms to the principle of linear superposition;

[0017] (2) The precipitation well is an incomplete well, with constant-flow pumping. Only the flow of water in the aquifer is considered, and the influence of the precipitation well on seepage is not considered. The phreatic flow towards the well in the precipitation well is horizontal, the equipotential surface is a coaxial cylindrical surface and is consistent with the cross-sectional area of the flowing water. The flow rate through different cross-sectional areas of the flowing water is equal everywhere and is equal to the flow rate towards the well;

[0018] (3) The influence of position head and pressure head is considered, and the influence of velocity head is not considered;

[0019] (4) The precipitation wells are only arranged within the excavation area of the foundation pit and are within the range below the bottom surface of the excavation area of the foundation pit;

[0020] (5) Only the number, position, depth and flow rate of the precipitation wells are considered;

[0021] (6) The diaphragm wall is used as the water-stop curtain for the foundation pit, and the water-stop curtain is located at the excavation boundary of the foundation pit.

[0022] Furthermore, in step 2, the modeling parameters of the numerical model for foundation pit dewatering seepage analysis include geometric parameters, material parameters, load boundary parameters, analysis parameters, grid parameters and initial parameters of the precipitation wells.

[0023] Furthermore, the geometric parameters include a geometric dimension model representing the size of the foundation pit and the size of the precipitation wells, and also include the formation distribution of the foundation pit and the precipitation layer, the distribution of the initial water level surface of the foundation pit, the dewatering area boundary of the foundation pit, the position and length of the water-stop curtain of the foundation pit and the layout parameters of the precipitation wells,

[0024] The material parameters include the permeability coefficient of the formation,

[0025] The analysis parameters include the transient seepage analysis parameters of the Dupuit formula,

[0026] The grid parameters include the grid element type, and the grid element type includes pore pressure elements, grid element size and the number of grid nodes,

[0027] The initial parameters of the precipitation wells include the initial number n0 of the precipitation wells, and also include the position (x, y, z) and depth l of the precipitation wells.

[0028] Furthermore, the specific implementation of step 4 includes the following steps:

[0029] Step (41): Initialize each parameter of the numerical model for foundation pit dewatering seepage analysis, including setting the initial number of precipitation wells as n0, the step length n for representing the increase in the number of precipitation wells in each iteration s , the depth range of the precipitation wells is [l min , l max , that is, the depth l of any precipitation well satisfies l min ≤ l ≤ lmax , set the precipitation time t i , set the flow rate q0 per unit length of a single precipitation well, set the maximum number of iterations m, and use j to represent the iteration count.

[0030] According to the allowable range of the precipitation well location and the allowable range of the depth, randomly generate the initial location and initial length of the precipitation well to obtain the elements characterizing the precipitation well location and length. The element of the i-th precipitation well is denoted as w i (x i , y i , z i , l i ), and the set of each element is {w1(x1, y1, z1, l1), w2(x2, y2, z2, l2), …, w i (x i , y i , z i , l i ), …},

[0031] Regard the entire excavation area of the foundation pit as the precipitation target area Z, and require the water level in the precipitation target area to be lower than the preset length threshold below the water-resisting floor p3;

[0032] Step (42): Based on the initialized parameters, calculate the numerical model of the foundation pit precipitation seepage analysis, and judge whether the water level elevation at any point in the precipitation target area Z is ≤ h s , that is, for any i, it satisfies h i ≤ h s . If not, execute step (43); if so, calculate the total inflow Q, and save the precipitation well layout data of each precipitation well at this time, so as to obtain the precipitation well layout data set J(x), J(x) = {{w1(x1, y1, z1, l1), w2(x2, y2, z2, l2), …, w i (x i , y i , z i , l i ), …}, Q}, and then, execute step (43);

[0033] Step (43): Increment the iteration count j by 1, that is, j = j + 1, and judge whether the current number of iterations j satisfies j < m. If so, based on the Latin hypercube sampling method, within the allowable range of the precipitation well location and the allowable range of the depth, randomly generate a new set of precipitation well locations and lengths again;

[0034] Step (44): Based on the newly generated precipitation well locations and lengths, calculate the water level elevation corresponding to the precipitation well locations and lengths of this group again, and judge whether the water level elevation at any point in the precipitation target area Z is ≤ hs If not, return to step (43) until the iteration number j reaches the maximum iteration number m, that is, j = m, then end the calculation of the initial number of precipitation wells n0 in this round;

[0035] Step (45): In this round of calculation, determine whether the precipitation well layout data set J(x) is empty.

[0036] If it is empty, increase the number of precipitation wells. The new number of precipitation wells n = n0 + n s , n s is a constant, and then jump back to step (41), that is, the iteration number j is reset to 1, and re - calculate this round with the new number of precipitation wells until the precipitation well layout data set J(x) is non - empty.

[0037] If it is non - empty, take the number, location and length of the precipitation wells corresponding to the minimum total inflow as the design optimization result to obtain the optimized result of the precipitation well layout.

[0038] A processing terminal, which includes:

[0039] A memory for storing program instructions;

[0040] A processor for running the program instructions to execute the steps of the optimization method for the foundation pit precipitation well layout.

[0041] The beneficial effects of the present invention: The optimized result of the foundation pit precipitation well obtained by the present invention can better meet the actual requirements of the number, location and depth of the precipitation wells. The setting of the precipitation wells is more matched with the requirements, avoiding waste, and achieving the effects of economic energy conservation and environmental protection. In addition, for the problem of precipitation well layout in foundation pit precipitation, based on the basic assumptions required for numerical simulation, a numerical model is established, the optimization objectives and optimization principles are set, and the optimal precipitation well layout under the current working conditions is obtained, including the number of precipitation wells, the optimal location, length and flow rate. The described optimization method is clear and straightforward. Based on the actual working conditions, an analysis model is established by combining with numerical simulation software, and through optimization iterative calculation, the optimal precipitation well layout under this working condition can be obtained. Compared with the existing foundation pit precipitation well layout methods, it carefully considers the influence of the number, location, length and flow rate of the precipitation wells, the optimization objectives are more clear, it is more closely combined with the actual working conditions and more flexible in application, and is applicable to the precipitation well layout problems in various foundation pit projects. Description of the Drawings

[0042] Figure 1 is the flow chart of the present invention;

[0043] Figure 2 is the schematic diagram of the foundation pit and precipitation wells in three - dimensions;

[0044] Figure 3 is the schematic diagram of the graphical illustration of relevant parameters;

[0045] Figure 4 It is a schematic diagram of a foundation pit and a precipitation well in a two-dimensional plane and includes the distribution of each precipitation well.

[0046] Figure 5 It is a schematic diagram of the structure of a processing terminal. Specific implementation manners

[0047] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation schemes:

[0048] As Figures 1-4 shown, an optimization method for the layout of foundation pit precipitation wells includes the following steps:

[0049] Step 1: Set the assumption conditions of the foundation pit precipitation seepage analysis model. The assumption conditions characterize the parameters of the foundation pit precipitation seepage analysis model, and the foundation pit precipitation seepage analysis model is used to analyze the water seepage situation of the foundation pit precipitation wells.

[0050] The purpose of setting the assumption conditions is to enable the foundation pit precipitation seepage analysis model to find the optimal solution and meet the convergence conditions based on the numerical simulation mathematical method, so as to ensure the rationality and accuracy of the calculation results. At the same time, by appropriately reducing some unnecessary or less influential factors, it is convenient to balance between the solution and meeting the actual layout requirements of the final foundation pit precipitation wells.

[0051] The assumption conditions are an appropriate simplification of the actual situation of the foundation pit precipitation well layout. The optimal solution (analytical solution) obtained according to such assumption conditions has been proven in engineering practice to be applicable to the actual situation, and its error degree is within an acceptable range. And through the assumption conditions, the rationality of the calculation results is ensured, and the feasibility and simplicity of the numerical simulation mathematical method are also ensured.

[0052] Exemplarily, the assumption conditions include:

[0053] (1) The simulated seepage layer of the foundation pit precipitation seepage analysis model is a finite phreatic aquifer with constant head lateral recharge and no vertical recharge. The aquifer is homogeneous and isotropic. Before precipitation, the initial water head of the aquifer is horizontal, the impervious floor of the foundation pit precipitation well is horizontal, the water level and flow rate of a single foundation pit precipitation well both conform to the steady well flow model of Dupuit, and the precipitation of the group wells composed of all foundation pit precipitation wells conforms to the linear superposition principle.

[0054] (2) The precipitation well (i.e., the foundation pit precipitation well) is an incomplete well, pumping at a constant flow rate. Only the flow of water in the aquifer is considered, and the influence of the precipitation well on seepage is not considered. The phreatic flow in the precipitation well flowing into the well is horizontal, the equipotential surface is a coaxial cylindrical surface, and is consistent with the cross-sectional area of flow. The flow rate through different cross-sectional areas of flow is everywhere equal and is equal to the flow rate flowing into the well.

[0055] (3) Consider the position head and pressure head, and do not consider the influence of velocity head.

[0056] (4) Simulate the in-pit dewatering of the foundation pit, that is, the dewatering wells are only arranged within the excavation area of the foundation pit and are within the range below the bottom surface of the excavation area of the foundation pit.

[0057] (5) Only consider the number, position, depth and flow rate of the dewatering wells, including not considering the influence of the radius of the dewatering wells, not considering the limit of the maximum allowable discharge of a single dewatering well, and not considering other layout parameters of the dewatering wells, that is, not considering the layout parameters of the dewatering wells other than the number, position, depth and flow rate of the dewatering wells.

[0058] (6) The diaphragm wall is used as the water-stop curtain for the foundation pit, and the water-stop curtain is located at the excavation boundary of the foundation pit.

[0059] Among the above assumptions, the seepage layer is set as a finite phreatic aquifer with constant head lateral recharge and no vertical recharge, that is, the seepage layer is set as laminar flow. Although, in reality, the seepage layer is generally turbulent flow and there is no completely theoretical laminar flow. However, according to actual engineering and existing research, the optimal solution obtained based on setting the seepage layer as laminar flow can be applied to the actual foundation pit dewatering well project. Although there are errors, the errors are within an acceptable range, and after such setting, it can well improve the feasibility and simplicity in the numerical simulation mathematical processing method.

[0060] Step 2: Based on the above assumptions, establish a numerical model for the foundation pit dewatering seepage analysis model to obtain the foundation pit dewatering seepage analysis numerical model.

[0061] Exemplarily, the modeling parameters of the foundation pit dewatering seepage analysis numerical model include geometric parameters, material parameters, load boundary parameters, analysis parameters, grid parameters and initial parameters of the dewatering wells.

[0062] The geometric parameters include the geometric dimension model representing the size of the foundation pit and the dewatering wells, and also include the formation distribution of the foundation pit and the seepage layer, the initial water level surface distribution of the foundation pit, the dewatering area boundary of the foundation pit, the position and length of the water-stop curtain of the foundation pit and the layout parameters of the dewatering wells.

[0063] Reference Figure 2 , the length of the excavation area (range) of the dewatering well is L x and the width is L y and the height is L z . The dewatering well is located within the foundation pit, and the length of the excavation area of the foundation pit is M x and the width is M y and the height is M z . For example, the length, width and height of the dewatering well are 50 m (meters) × 60 m × 10 m, that is, L x= 50 m, L y = 60 m, L z = 10 m. The excavation range of the foundation pit is expanded 2 times respectively in the x, y, and z directions on the basis of the excavation area of the dewatering well. Therefore, the length, width, and height of the foundation pit are 150 m × 180 m × 30 m, that is, M x = 150 m, M y = 180 m, M z = 30 m. The stratum of the foundation pit is a horizontally homogeneous stratum. Taking the lower left corner of the foundation pit as the coordinate origin (0, 0, 0), and taking the bottom surface of the foundation pit as the reference elevation, the elevation here is zero. The initial water level of the foundation pit is at the ground surface, that is, at the elevation z0 = 30 m of the initial water level. The length of the cut-off curtain is taken as half of the elevation of the initial water level, that is, the cut-off curtain value is 15 m.

[0064] The material parameters include the permeability coefficient of the stratum. In this embodiment, the permeability coefficient k of the stratum is 1 m 3 / d (cubic meters per day).

[0065] The load boundary parameters include the seepage boundary conditions. The seepage boundary conditions include that the bottom surface of the foundation pit is an impermeable surface, a linear pore pressure boundary is applied to the side surface of the foundation pit, and the upper surface (i.e., the ground surface) of the foundation pit is a free seepage surface.

[0066] The analysis parameters include the transient seepage analysis parameters of Dupuit's formula.

[0067] The mesh parameters include the mesh element type. The mesh element type includes pore pressure elements, mesh element size, and the number of mesh nodes. The mesh element size is taken as 1 m. The number of mesh nodes is exported for subsequent node flow rate settings.

[0068] The initial parameters of the dewatering well include the initial number n0 of the dewatering wells, n0 > 1, and also include the position (x, y, z) and depth l of the dewatering well.

[0069] Reference Figure 3 and Figure 4 , only considering the xoy plane, the position of the i-th dewatering well is denoted as w i (x i , y i ), that is, the coordinates of the i-th dewatering well w i are (x i , y i ), and the depth of the i-th dewatering well is l i . The total flow rate q of a single dewatering well is q = q0 * l, where q0 represents the flow rate per unit length of the dewatering well. Therefore, the total flow rate q i = q 0,i * l i , q 0,iRepresents the flow rate per unit length of the i-th precipitation well.

[0070] Among them, z0 represents the initial water level elevation, z1 represents the length of the cut-off curtain, W0 represents the cut-off curtain, p0 represents the ground surface, p1 represents the initial groundwater level, p2 represents the precipitation target water level surface, p3 represents the impervious floor, and Z represents the area where the foundation pit is located, which is also the precipitation target area, h i Represents that after the precipitation time is t i The water level elevation after precipitation, h s Represents the elevation of the precipitation target water level surface.

[0071] Step 3: Set the following objective function Obj:

[0072]

[0073] In the above formula, t represents time, t i Represents the set precipitation time. Therefore, h i ≤h s , Represents that after the precipitation time t i The water level elevation at any point within the precipitation target area Z is less than or equal to the elevation of the precipitation target water level surface. min(n) represents the minimum number of precipitation wells n, and min(Q) represents the minimum water inflow Q. That is, the above objective function Obj represents that after the precipitation time t i The water level elevation at any point within the target area Z is less than or equal to the elevation of the precipitation target water level surface, and the minimum water inflow under the minimum number of precipitation wells is used as the solution target.

[0074] Step 4: Using the above objective function Obj as a constraint condition, perform iteration on the numerical model of foundation pit precipitation seepage analysis. The optimal solution of the iteration is used as the final optimization result of precipitation well design, including the number of precipitation wells, their positions, and the depths corresponding to each precipitation well.

[0075] More specifically, it includes the following steps:

[0076] Step (41): Initialize each parameter of the numerical model of foundation pit precipitation seepage analysis, including setting the initial number of precipitation wells as n0, and the step size n used to characterize the increase in the number of precipitation wells in each iteration s . For example, n0 = 15, n s = 2. The depth range of the precipitation wells is [l min , l max . That is, the depth l of any precipitation well satisfies l min ≤l≤l max . Set the precipitation time t i . In this embodiment, t i= 2d (days), which means 48 hours. Set the unit length flow rate q0 of a single precipitation well to 10 m 3 / d. Set the maximum number of iterations m. In this embodiment, m = 300. The iteration count is represented by j, that is, the j-th iteration.

[0077] According to the allowed range of the precipitation well location and the allowed range of the depth, randomly generate the initial position and initial length of the precipitation well. Both the initial position and the initial length need to be within the allowed range. Obtain the elements representing the precipitation well location and length. The element of the i-th precipitation well is denoted as w i (x i , y i , z i , l i ), and each set of elements is {w1(x1, y1, z1, l1), w2(x2, y2, z2, l2), …, w i (x i , y i , z i , l i ), …}.

[0078] The entire excavation area of the foundation pit is used as the precipitation target area Z, that is, the entire foundation pit is the precipitation target area, and it is required that the water level in the precipitation target area is lower than the waterproof base plate p3 by a preset length threshold. In this implementation, the preset length threshold is 0.5 m. That is, it is required that the water level is 0.5 m and below under the waterproof base plate p3 of the foundation pit, that is, at least 0.5 m lower than the waterproof base plate p3.

[0079] Step (42): Based on the initialized parameters, calculate the numerical model of the foundation pit precipitation seepage analysis, and judge whether the water level elevation at any point in the precipitation target area Z is ≤ h s , that is, for any i, it satisfies h i ≤ h s . If not, execute step (43); if so, calculate the total water inflow Q, and save the precipitation well layout data of each precipitation well at this time, so as to obtain the precipitation well layout data set J(x), J(x) = {{w1(x1, y1, z1, l1), w2(x2, y2, z2, l2), …, w i (x i , y i , z i , l i ), …}, k}, and then, execute step (43).

[0080] Step (43): The iteration count j is increased by 1, i.e., j=j+1, and it is determined whether the current iteration number j satisfies j<m. If so, a new set of precipitation well positions and lengths are randomly generated based on the Latin hypercube sampling method within the range allowed by the precipitation well position and the range allowed by the depth. For example, in the second iteration (i.e., j=2), a new set of precipitation well positions and lengths are regenerated as {w1(86,93,20,8),w2(88,100,23,12),…,w i (x i ,y i ,z i ,l i ),…}.

[0081] Step (44): Based on the newly generated precipitation well position and length, the water level elevation corresponding to the precipitation well position and length of this group is calculated again, and it is determined whether the water level elevation at any point in the precipitation target area Z is ≤ h s If not, return to step (43) until the number of iterations j reaches the maximum number of iterations m, that is, j = m, and then the calculation of the initial number of dewatering wells in this round is terminated.

[0082] Step (45): In this round of calculation, determine whether the precipitation well layout data set J(x) is empty. If it is empty, the number of surface precipitation wells is n0. It is impossible to find a precipitation well layout that meets the conditions, that is, it is impossible to find a precipitation well layout that meets the objective function Obj. Therefore, it is necessary to increase the number of precipitation wells. The new number of precipitation wells n = n0 + n s , n s It can be taken as 2. Therefore, based on the original n0=15, the number of precipitation wells in this round is n=17, and the process jumps to step (41) again, that is, the number of iterations j is reset to 1, and the calculation of this round is performed again with the new number of precipitation wells, until the precipitation well layout data set J(x) is non-empty. If it is non-empty, the number, position and length of precipitation wells corresponding to the minimum total water inflow are taken as the design optimization result, and the precipitation well layout optimization result is obtained. That is, the number of precipitation wells, the position of precipitation wells and the length of each precipitation well corresponding to the minimum total water inflow min(Q) are the final precipitation well layout optimization results.

[0083] like Figure 5 As shown, the present invention also provides a processing terminal 100, which includes:

[0084] Memory 101, used for storing program instructions;

[0085] The processor 102 is used to run the program instructions to execute the steps of the foundation pit dewatering well layout optimization method.

[0086] In view of the problem of the layout of dewatering wells in foundation pit dewatering, the present invention makes basic assumptions based on numerical simulation requirements, establishes a numerical model, sets optimization objectives and optimization principles, and obtains the optimal layout of dewatering wells under the current working conditions, including the number of dewatering wells, the optimal positions, lengths and flow rates. The optimization method is clear and straightforward. Based on the actual working conditions and combined with a numerical simulation software to establish an analysis model and conduct optimization iterative calculations, the optimal layout of dewatering wells under this working condition can be obtained. Compared with the existing methods for the layout of foundation pit dewatering wells, the influence of the number, position, length and flow rate of dewatering wells is considered in a more refined manner, the optimization objectives are more clear, the combination with the actual working conditions is closer and the application is more flexible, and it is applicable to the layout problems of dewatering wells in various foundation pit projects.

[0087] The embodiments disclosed in this specification are only an illustration of the unilateral features of the present invention. The protection scope of the present invention is not limited to this embodiment, and any other functionally equivalent embodiments fall within the protection scope of the present invention. For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all such changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for optimizing the layout of foundation pit dewatering wells, characterized in that: The following steps are involved: Step 1: Set the assumptions of the foundation pit dewatering seepage analysis model. The assumptions represent the parameters of the foundation pit dewatering seepage analysis model. The foundation pit dewatering seepage analysis model is used to analyze the seepage of the foundation pit dewatering well. Step 2: Based on the assumptions, a numerical model is established for the foundation pit dewatering seepage analysis model to obtain a foundation pit dewatering seepage analysis numerical model; Step 3: Set the following objective function Obj: In the above formula, t represents time, t i Indicates the set precipitation time, h i ≤h s , represents the precipitation time t i After that, the water level elevation at any point in the precipitation target area Z is less than or equal to the precipitation target water level elevation, min(n) represents the minimum number of precipitation wells n, min(Q) represents the minimum water inflow Q, The above objective function Obj represents the precipitation time t. i After that, the water level at any point in the target area Z is less than or equal to the precipitation target water level, and the minimum water inflow under the minimum number of precipitation wells is taken as the solution target; Step 4: Using the above objective function Obj as a constraint condition, the numerical model of foundation pit dewatering seepage analysis is iterated, and the optimal solution of the iteration is used as the final dewatering well design optimization result, including the number, location and corresponding depth of each dewatering well.

2. The method for optimizing the layout of foundation pit dewatering wells according to claim 1, characterized in that: In step 1, the assumptions include: (1) The simulated seepage layer of the foundation pit dewatering seepage analysis model is a finite phreatic aquifer with a constant head lateral recharge and no vertical recharge. The aquifer is homogeneous and isotropic. Before dewatering, the initial water head of the aquifer is horizontal, and the waterproof bottom plate of the foundation pit dewatering well is horizontal. The water level and flow rate of a single foundation pit dewatering well conform to Qiu Buyi's steady well flow model, and the dewatering of the group of wells composed of all foundation pit dewatering wells conforms to the linear superposition principle. (2) The precipitation well is an incomplete well. It is pumped at a constant flow rate. Only the flow of water in the aquifer is considered, and the impact of the precipitation well on the seepage is not considered. The submerged flow in the precipitation well to the well is horizontal. The equal head surface is a coaxial cylindrical surface and is consistent with the water flow section. The flow through different water flow sections is equal everywhere and equal to the flow to the well. (3) Considering the position head and pressure head, ignoring the influence of velocity head; (4) The drainage well is only arranged in the excavation area of ​​the foundation pit and is located below the bottom surface of the excavation area of ​​the foundation pit; (5) Only the number, location, depth and flow rate of precipitation wells are considered; (6) The foundation pit uses an underground continuous wall as a water-stop curtain, which is located at the excavation boundary of the foundation pit.

3. The method for optimizing the layout of foundation pit dewatering wells according to claim 1, characterized in that: In step 2, the modeling parameters of the numerical model for foundation pit dewatering seepage analysis include geometric parameters, material parameters, load boundary parameters, analysis parameters, mesh parameters, and initial parameters of the dewatering well.

4. The method for optimizing the layout of foundation pit dewatering wells according to claim 3, characterized in that: The geometric parameters include the geometric size model that characterizes the size of the foundation pit and the size of the drainage well, as well as the stratigraphic distribution that characterizes the foundation pit and the drainage layer, the initial water level surface distribution of the foundation pit, the drainage area boundary of the foundation pit, the location and length of the water-stop curtain of the foundation pit, and the layout parameters of the drainage well. The material parameters include the permeability coefficient of the formation, The analysis parameters include transient seepage analysis parameters of the Joubuy formula, The grid parameters include grid unit type, which includes pore pressure unit, grid unit size and grid node number. The initial parameters of the precipitation wells include the initial number n0 of the precipitation wells, and also include the location (x, y, z) and depth l of the precipitation wells.

5. The method for optimizing the layout of foundation pit dewatering wells according to claim 1, characterized in that: The specific implementation of step 4 includes the following steps: Step (41): Initialize various parameters of the numerical model for foundation pit dewatering seepage analysis, including setting the initial number of dewatering wells to n0 and the step length n used to characterize the increase in the number of dewatering wells in each iteration. s , the depth range of the precipitation well is [l min ,l max ], that is, the depth l of any precipitation well satisfies l min ≤l≤l max , set the precipitation time t i , set the unit length flow rate q0 of a single precipitation well, set the maximum number of iterations m, and the iteration count is represented by j, According to the allowed range of the precipitation well position and the allowed range of the depth, the initial position and initial length of the precipitation well are randomly generated to obtain the elements representing the position and length of the precipitation well. The element of the i-th precipitation well is recorded as w i (x i ,y i ,z i ,l i ), the element set is {w1(x1,y1,z1,l1),w2(x2,y2,z2,l2),…,w i (x i ,y i ,z i ,l i ),…}, The entire excavation area of ​​the foundation pit is used as the precipitation target area Z, and the water level in the precipitation target area is required to be lower than the preset length threshold below the waterproof bottom plate p3; Step (42): Based on the initialized parameters, the numerical model for foundation pit dewatering seepage analysis is calculated to determine whether the water level elevation at any point in the dewatering target area Z is ≤ h s , that is, for any i, h i ≤h s , if not, execute step (43); if yes, calculate the total water inflow Q, and save the precipitation well layout data of each precipitation well at this time, so as to obtain the precipitation well layout data set J(x), J(x)={{w1(x1,y1,z1,l1),w2(x2,y2,z2,l2),…,w i (x i ,y i ,z i ,l i ),…},Q}, then, execute step (43); Step (43): the iteration count j is increased by 1, i.e., j=j+1, and it is determined whether the current iteration number j satisfies j<m. If so, a new set of precipitation well positions and lengths are randomly generated based on the Latin hypercube sampling method within the range allowed by the precipitation well position and the range allowed by the depth. Step (44): Based on the newly generated precipitation well position and length, the water level elevation corresponding to the precipitation well position and length of this group is calculated again, and it is determined whether the water level elevation at any point in the precipitation target area Z is ≤ h s If not, return to step (43) until the number of iterations j reaches the maximum number of iterations m, that is, j = m, and then the calculation of the initial number of precipitation wells in this round is terminated as n0; Step (45): In this round of calculation, determine whether the precipitation well layout data set J(x) is empty. If it is empty, increase the number of precipitation wells, the new number of precipitation wells n = n0 + n s , n s is a constant, and jumps back to step (41), that is, the number of iterations j is reset to 1, and the calculation of this round is performed again with the new number of precipitation wells until the precipitation well arrangement data set J(x) is non-empty. If it is not empty, the number, location and length of the precipitation wells corresponding to the minimum total water inflow will be taken as the design optimization result to obtain the optimization result of the precipitation well layout.

6. A processing terminal, characterized in that: It includes: A memory for storing program instructions; A processor is used to run the program instructions to execute the steps of the method for optimizing the layout of foundation pit dewatering wells as described in any one of claims 1 to 5.

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