Prediction method for soil body settlement of each stratum caused by foundation pit dewatering in multi-layer aquifer region
Through on-site pumping tests, indoor geotechnical tests and numerical model calculations, the problem of insufficient soil settlement prediction caused by deep foundation pit precipitation in multiple aquifers was solved, and accurate settlement prediction and effective precipitation plan were achieved, reducing the risk of ground settlement.
Patent Information
- Application Number
- CN202410168557.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2025-08-08
AI Technical Summary
In the process of precipitation of deep foundation pits in multiple aquifer areas, it is difficult to accurately predict the settlement patterns of soils on the surface and different formations, resulting in uneven settlement may cause accidents such as ground cracks or building cracks, especially insufficient research on weak permeable layers.
Through on-site pumping tests, indoor geotechnical tests, on-site precipitation tests and indoor simulations, relevant parameters of soil sedimentation caused by deep foundation pit precipitation in multiple aquifers were obtained, and the impact of different precipitation plans was calculated using numerical models, and targeted precipitation plans were formulated to reduce the impact of settlement.
Accurate prediction of soil sedimentation in surface and different formations caused by precipitation of deep foundation pits in multiple aquifer areas was achieved, and effective precipitation plans were formulated to reduce the impact of settlement on surrounding grounds and reduce the risk of accidents.
Smart Images
Figure CN120443689A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of construction safety management, and in particular relates to a method for predicting settlement of the ground surface and soil in different strata caused by dewatering of a deep foundation pit in a multi-layer aquifer area. Background Art
[0002] Deep foundation pit dewatering can cause varying degrees of uneven settlement of the surrounding ground, leading to severe damage such as ground fissures or cracks in buildings. Rail transit projects inevitably involve a large number of deep foundation pits and deep foundation pit dewatering projects. As foundation pits become larger and deeper, involving multiple aquifers and aquitards, improper dewatering measures can easily lead to foundation pit accidents. Ground subsidence caused by deep foundation pit dewatering is closely linked to environmental, economic, and social issues, and has become a pressing issue that needs to be addressed during foundation pit construction.
[0003] Most existing studies focus on the settlement of strong or highly permeable layers during dewatering, while less attention is paid to the settlement of weak permeable layers under pumping conditions. There is a lack of research on ground settlement caused by dewatering in deep foundation pit projects in areas with multi-layer aquifers containing weak permeable layers. Ground settlement caused by foundation pit dewatering is caused by the combined effect of deformation of different soil layers. Current research focuses more on the overall settlement amount and less on the actual deformation and development patterns of different soil layers. Under dewatering conditions, the deformation patterns of aquifers and weak permeable layers are bound to be very different. In-depth research on the deformation patterns of different surrounding soil layers caused by deep foundation pit dewatering in areas with multi-layer aquifers, and accurate prediction of surface and different stratum soil settlement caused by deep foundation pit dewatering under different working conditions before excavation, is of great significance for deep foundation pit dewatering and drainage plans, subsequent excavation guidance, and the implementation of effective preventive measures. Summary of the Invention
[0004] The purpose of the present invention is to provide a method for predicting the settlement of the ground surface and different strata caused by dewatering of deep foundation pits in multi-layer aquifer areas, so as to overcome the shortcomings of the existing technology.
[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: The method for predicting soil settlement in each stratum caused by foundation pit dewatering in a multi-layer aquifer area includes the following steps: Step 1: Obtain the hydrogeological parameters of each stratum in the construction area through pumping test; Step 2: Conduct indoor geotechnical tests by drilling samples on site to obtain the physical and mechanical parameters of each stratum in the construction area; Step 3: Select a part of the construction area to conduct an on-site precipitation-induced ground settlement test on the construction area; Step 4: Simulate the settlement of the ground and different strata caused by different precipitation schemes indoors; Step 5: The numerical model calculates the impact of different precipitation schemes on the settlement of the surrounding ground and different strata; Step 6: Based on the numerical simulation results, predict the surface and different stratum soil settlement caused by deep foundation pit dewatering in multi-layer aquifer areas under different dewatering schemes.
[0006] To further optimize this technical solution, in step 3, the area selected for the on-site precipitation-induced ground settlement test and the design of the precipitation plan should minimize the impact on ground settlement and not affect surrounding buildings and pipelines.
[0007] To further optimize this technical solution, in step 3, when conducting an on-site precipitation test, surrounding groundwater level observation, ground subsidence monitoring, and settlement monitoring of soil in different strata should be carried out simultaneously with precipitation.
[0008] To further optimize this technical solution, in step 4, the physical model of the multi-layer aquifer area for indoor simulation should be replicated in proportion to the on-site strata to restore the on-site strata and hydrogeological conditions as much as possible.
[0009] To further optimize this technical solution, in step 4, different precipitation schemes include but are not limited to different water-stop curtain depths, different numbers of precipitation wells, different precipitation well depths, different precipitation well distributions, etc.
[0010] To further optimize this technical solution, in step 4, water level observation of simulated strata, ground subsidence monitoring, and settlement monitoring of soil masses in different strata should be carried out when different indoor precipitation schemes are implemented.
[0011] To further optimize this technical solution, in step 5, the selected numerical simulation software should reflect as accurately as possible the results of the settlement of the surrounding ground and soil in different strata caused by the on-site dewatering simulation in step 3, and the results of the settlement of the surrounding ground and soil in different strata caused by the indoor simulation of foundation pit dewatering under different dewatering schemes in step 4.
[0012] To further optimize this technical solution, in step 5, the parameters related to the surface and different stratum soil settlement caused by deep foundation pit dewatering used for numerical simulation calculation are obtained by mutual verification and correction of the test results obtained in steps 1, 2, 3 and 4.
[0013] To further optimize this technical solution, in step 5, the settlement of the ground surface and different strata soil caused by different deep foundation pit dewatering schemes is predicted.
[0014] To further optimize this technical solution, in step 6, based on the settlement of the ground and soil in different strata caused by deep foundation pit dewatering in the multi-layer aquifer area predicted in step 5, the settlement of the ground and soil in different strata caused by deep foundation pit dewatering in the multi-layer aquifer area under different dewatering schemes is predicted, and corresponding foundation pit dewatering schemes and corresponding preventive measures are proposed in a targeted manner for the settlement of different strata, so as to minimize the impact of deep foundation pit dewatering on the surrounding ground settlement.
[0015] Compared with the existing technology, the present invention provides a method for predicting the settlement of the ground surface and different strata caused by dewatering of deep foundation pits in multi-layer aquifer areas, which has the following beneficial effects: Compared with the prior art, the method provided by the present invention is for predicting the settlement of the surface and soil in different strata caused by dewatering of deep foundation pits in multi-layer aquifer areas. The method obtains the relevant parameters of the settlement of the surface and soil in different strata caused by dewatering of deep foundation pits in multi-layer aquifer areas through on-site pumping tests, indoor geotechnical tests, on-site settlement tests of the surface and soil in different strata caused by dewatering, and indoor simulations of the settlement of the surface and soil in different strata caused by different dewatering schemes. The relevant parameters are substituted into the numerical model to calculate the settlement amount and settlement distribution of the surface and soil in different strata caused by different dewatering schemes, and the settlement of the surface and soil in different strata caused by dewatering of deep foundation pits in multi-layer aquifer areas is predicted. Based on the simulation results, foundation pit dewatering schemes are formulated in a targeted manner according to the settlement conditions of different strata, so that effective preventive measures can be taken to reduce the impact of dewatering of deep foundation pits in multi-layer aquifer areas on the settlement of surrounding surface and soil in different strata. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The present invention is a flowchart of a method for predicting surface and different stratum soil settlement caused by deep foundation pit dewatering in multi-layer aquifer areas. Specific embodiments
[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0018] Example 1: Prediction of surface and different stratum soil settlement caused by deep foundation pit dewatering in a multi-layer aquifer area at different foundation pit water-stop curtain depths See also Figure 1 A method for predicting surface and different stratum soil settlement caused by dewatering of a deep foundation pit in a multi-layer aquifer area comprises the following steps: Step 1: Obtain the hydrogeological parameters of each stratum in the construction area through pumping test; Step 2: Conduct indoor geotechnical tests by drilling samples on site to obtain the physical and mechanical parameters of each stratum in the construction area; Step 3: Select a part of the construction area to conduct a field test on ground settlement caused by precipitation in the construction area to obtain the settlement patterns of the surrounding ground and different strata during the on-site precipitation process; Step 4: Conduct indoor simulations of the settlement of the ground and soil in different strata caused by foundation pit dewatering at different foundation pit water-stop curtain depths. The specific depth of the water-stop curtain is set according to research requirements and can be divided into insertion into a partial aquifer, insertion into one or more aquifers, and barrier aquifers, etc., to obtain the settlement patterns of the surrounding ground and soil in different strata caused by dewatering at different foundation pit water-stop curtain depths; Step 5: Based on the obtained hydrogeological parameters of the construction area, the physical and mechanical parameters of each stratum, and the on-site and indoor dewatering test simulations, a numerical model is used to calculate the impact of dewatering at different foundation pit water-stop curtain depths on the settlement of the surrounding ground and soil in different strata; Step 6: Based on the numerical simulation results, predict the surface and different stratum soil settlement caused by deep foundation pit dewatering in multi-layer aquifer areas under different dewatering schemes, and formulate reasonable deep foundation pit dewatering schemes and settlement prevention measures for specific aquifers to reduce the impact of deep foundation pit dewatering on surrounding ground settlement.
[0019] To further optimize this technical solution, in step 3, the area selected for the on-site precipitation-induced ground settlement test and the design of the precipitation plan should minimize the impact on ground settlement and not affect surrounding buildings and pipelines.
[0020] To further optimize this technical solution, in step 3, when conducting an on-site precipitation test, surrounding groundwater level observation, ground subsidence monitoring, and settlement monitoring of soil in different strata should be carried out simultaneously with precipitation.
[0021] To further optimize this technical solution, in step 4, the physical model of the multi-layer aquifer area for indoor simulation should be replicated in a certain proportion to the on-site strata to restore the on-site strata and hydrogeological conditions as much as possible.
[0022] To further optimize this technical solution, in step 4, different depths of foundation pit water-stop curtains include but are not limited to inserting into a part of the aquifer, inserting into one or more aquifers, and blocking the aquifer, etc.
[0023] To further optimize this technical solution, in step 4, water level observation of simulated strata, ground subsidence monitoring, and settlement monitoring of soil masses in different strata should be carried out when different indoor precipitation schemes are implemented.
[0024] To further optimize this technical solution, in step 5, the selected numerical simulation software should be able to accurately reflect the results of the settlement of the surrounding ground and soil in different strata caused by the on-site dewatering test in step 3, as well as the results of the settlement of the surrounding ground and soil in different strata caused by the indoor simulation of foundation pit dewatering under different dewatering schemes in step 4.
[0025] To further optimize this technical solution, in step 5, the parameters related to the surface and different stratum soil settlement caused by deep foundation pit dewatering used for numerical simulation calculation are obtained by mutual verification and correction of the test results obtained in steps 1, 2, 3 and 4.
[0026] To further optimize this technical solution, in step 5, the settlement of the ground surface and different strata soil caused by different deep foundation pit dewatering schemes is predicted.
[0027] To further optimize this technical solution, in step 6, based on the settlement of the ground and soil in different strata caused by deep foundation pit dewatering in multi-layer aquifer areas under different dewatering schemes predicted in step 5, corresponding foundation pit dewatering schemes and corresponding preventive measures are proposed in a targeted manner for the settlement of different strata, so as to minimize the impact of deep foundation pit dewatering on the surrounding ground settlement.
[0028] Example 2: Prediction of surface and different stratum soil settlement caused by deep foundation pit dewatering in a multi-layer aquifer area under different distributions of dewatering wells and recharge wells See also Figure 1 A method for predicting surface and different stratum soil settlement caused by dewatering of deep foundation pits in multi-layer aquifer areas, except for step 4, the remaining steps are the same as those in Example 1: Step 4: Simulate the settlement of the ground surface and soil in different strata caused by foundation pit dewatering under different indoor distributions of dewatering wells and recharge wells. The specific distribution of dewatering wells and recharge wells is set according to research needs, and can be divided into different distribution distances and shapes of dewatering wells and recharge wells to obtain the settlement rules of the surrounding ground and soil in different strata caused by foundation pit dewatering under different distributions of dewatering wells and recharge wells.
Claims
1. The prediction method of soil settlement in each layer caused by foundation pit dewatering in multi-layer aquifer areas is characterized by The following steps are involved: Step 1: Obtain the hydrogeological parameters of each stratum in the construction area through pumping test; Step 2: Conduct indoor geotechnical tests by drilling samples on site to obtain the physical and mechanical parameters of each stratum in the construction area; Step 3: Select a part of the construction area to conduct an on-site precipitation-induced ground settlement test on the construction area; Step 4: Simulate the settlement of the ground and different strata caused by different precipitation schemes indoors; Step 5: The numerical model calculates the impact of different precipitation schemes on the settlement of the surrounding ground and different strata; Step 6: Based on the numerical simulation results, predict the surface and different stratum soil settlement caused by deep foundation pit dewatering in multi-layer aquifer areas under different dewatering schemes.
2. The method according to claim 1, wherein In step 3, the area selected for the on-site precipitation-induced ground settlement test and the design of the precipitation plan should minimize the impact on ground settlement and not affect surrounding buildings and pipelines.
3. The method according to claim 1, wherein In step 3, when conducting the on-site precipitation test, the surrounding groundwater level observation, ground subsidence monitoring and settlement monitoring of soil in different strata are carried out simultaneously with the precipitation.
4. The method according to claim 1, wherein In step 4, the physical model of the multi-layer aquifer area simulated indoors is replicated in scale on the on-site strata.
5. The method according to claim 1, wherein In step 4, different dewatering schemes include different water-stop curtain depths, different numbers of dewatering wells, different dewatering well depths, and different dewatering well distributions.
6. The method according to claim 1, wherein In step 4, water level observation of simulated strata, ground subsidence monitoring, and settlement monitoring of soil masses in different strata are performed when different indoor precipitation schemes are implemented.
7. The method according to claim 1, wherein In step 5, the selected numerical simulation software accurately reflects the results of the settlement of the surrounding ground and soil in different strata caused by the on-site dewatering simulation in step 3, and the results of the settlement of the surrounding ground and soil in different strata caused by the foundation pit dewatering under different dewatering schemes in the indoor simulation in step 4.
8. The method according to claim 1, wherein In step 5, the parameters related to the settlement of the surface and soil in different strata caused by deep foundation pit dewatering used for numerical simulation calculation are obtained by mutual verification and correction of the test results obtained in steps 1, 2, 3 and 4.
9. The method according to claim 1, wherein In step 5, the settlement of the ground surface and soil in different strata caused by different deep foundation pit dewatering schemes is predicted.
10. The method according to claim 1, wherein In step 6, based on the settlement of the ground and soil in different strata caused by the deep foundation pit dewatering in the multi-layer aquifer area predicted in step 5, the settlement of the ground and soil in different strata caused by the deep foundation pit dewatering in the multi-layer aquifer area under different dewatering schemes is predicted, and corresponding foundation pit dewatering schemes and corresponding preventive measures are proposed in a targeted manner for the settlement of different strata, so as to minimize the impact of the deep foundation pit dewatering on the surrounding ground settlement.