A support structure and its deformation control method for ultra-deep foundation pit excavation.

Abstract

This invention discloses a support structure and its deformation control method for ultra-deep foundation pit excavation, applicable to the field of foundation pit support, including support structure design, deformation monitoring method, deformation monitoring and early warning scheme, and deformation control method; the support structure and its deformation control method for ultra-deep foundation pit excavation proposed in this invention have advantages such as high safety and construction efficiency, minimal impact on the surrounding environment, and low cost.

Description

Technical Field

[0001] This invention relates to a foundation pit support method, and more particularly to a support structure and deformation control method for ultra-deep foundation pit excavation. Background Technology

[0002] With the acceleration of urbanization, more and more high-rise buildings, underground parking garages, subways, and other projects need to be constructed in cities. These projects often require foundation pit excavation, which can have certain impacts on the surrounding environment, such as ground subsidence and building tilting. To meet different construction needs, the depth of foundation pit excavation varies. Ultra-deep foundation pits refer to foundation pits of extremely great depths that need to be excavated in construction, transportation, water conservancy, and other projects to meet the needs of buildings or to develop underground space. Generally speaking, ultra-deep foundation pits exceed 50 meters in depth and can even reach several hundred meters. Due to the greater depth of ultra-deep foundation pits, the stress conditions of the soil and rock involved in their excavation are more complex. Therefore, more stringent and complex support measures and deformation control methods are required to ensure construction safety and the stability of the surrounding environment. Summary of the Invention

[0003] The purpose of this invention is to provide a support structure and deformation control method for ultra-deep foundation pit excavation, which has the advantages of high safety and construction efficiency, minimal impact on the surrounding environment, and low cost.

[0004] The objective of this invention can be achieved by adopting the following technical solution:

[0005] S101, Support structure design: The support structure design includes two aspects, namely the design of horizontal support and the design of vertical support. The design of horizontal support includes anchor cables, and the design of vertical support includes foundation pit support piles. The foundation pit support piles are cast-in-place concrete piles.

[0006] S102, Deformation monitoring method: The deformation monitoring method includes measuring the change parameters of the foundation pit support by arranging monitoring points for the support structure. The monitoring points are arranged at the pile top and around the foundation pit. The monitoring points are divided into surface settlement monitoring points, horizontal displacement monitoring points of support piles, vertical displacement monitoring points of support piles, and foundation pit water level monitoring points according to different monitoring purposes.

[0007] S103, Deformation Monitoring and Early Warning Scheme: The deformation monitoring and early warning scheme includes setting early warning values, obtaining predicted values, and implementing the early warning. Setting early warning values ​​includes setting early warning values ​​for the daily deformation and total deformation of monitoring points. Obtaining predicted values ​​includes using a prediction model to learn from historical data of each monitoring point to obtain predicted values ​​for the next time interval. The method for constructing the prediction model is as follows: a) Data preparation: collect data from monitoring points, imputate missing values ​​using the mean imputation method, adjust the data to a time-displacement format, and divide the first 80% of the data into a training set and the last 20% into a test set. b) Construct a prediction model, which consists of two gated recurrent units and a dense recurrent network. The parameters for constructing the prediction model are input shape, gated recurrent unit size, regularization technique, optimizer selection, and loss function. c) Train the model using the training set data to obtain a trained model. d) Evaluate the model, which includes evaluating the performance of the trained model on the test set using root mean square error and mean absolute error. Based on the evaluation results, optimize the model to obtain an optimized model. The optimization mainly involves adjusting parameters. e) Use the optimized model to predict the data for the next time interval to obtain the predicted value.

[0008] The specific implementation of the early warning includes, based on the set early warning value and the predicted value, if the predicted value exceeds the early warning value, an early warning is issued and the deformation is controlled by the deformation control method; if the predicted value does not exceed the early warning value, the status quo is maintained and the deformation control method is not required.

[0009] S104, Deformation Control Method: The deformation control method includes strengthening the support structure, adjusting the excavation sequence, and controlling drainage. Strengthening the support structure includes adding a support structure on the existing basis to ensure the stability of the foundation pit. Adjusting the excavation sequence includes adjusting the excavation sequence and slowing down the excavation depth to reduce the amount and rate of deformation. Controlling drainage includes strengthening the foundation pit drainage system to reduce the influence of groundwater and ultimately reduce deformation. Strengthening the foundation pit drainage system includes setting more drainage holes at the bottom of the foundation pit and setting more drainage ditches around the foundation pit to lower the water level.

[0010] The beneficial effects of this invention are:

[0011] Compared with existing technologies, this invention provides a support structure and deformation control method for ultra-deep foundation pit excavation, which has advantages such as high safety and construction efficiency, minimal impact on the surrounding environment, and low cost. Attached Figure Description

[0012] Figure 1This is a flowchart of a support structure and deformation control method for ultra-deep foundation pit excavation construction according to the present invention. Detailed Implementation

[0013] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] like Figure 1 The diagram shown is a flowchart of a support structure and deformation control method for ultra-deep foundation pit excavation proposed in this invention. The flowchart includes the following contents.

[0015] S101, Support structure design: The support structure design includes two aspects, namely the design of horizontal support and the design of vertical support. The design of horizontal support includes anchor cables, and the design of vertical support includes foundation pit support piles. The foundation pit support piles are cast-in-place concrete piles.

[0016] S102, Deformation monitoring method: The deformation monitoring method includes measuring the change parameters of the foundation pit support by arranging monitoring points for the support structure. The monitoring points are arranged at the pile top and around the foundation pit. The monitoring points are divided into surface settlement monitoring points, horizontal displacement monitoring points of support piles, vertical displacement monitoring points of support piles, and foundation pit water level monitoring points according to different monitoring purposes.

[0017] S103, Deformation Monitoring and Early Warning Scheme: The deformation monitoring and early warning scheme includes setting early warning values, obtaining predicted values, and implementing the early warning. Setting early warning values ​​includes setting early warning values ​​for the daily deformation and total deformation of monitoring points. Obtaining predicted values ​​includes using a prediction model to learn from historical data of each monitoring point to obtain predicted values ​​for the next time interval. The method for constructing the prediction model is as follows: a) Data preparation: collect data from monitoring points, imputate missing values ​​using the mean imputation method, adjust the data to a time-displacement format, and divide the first 80% of the data into a training set and the last 20% into a test set. b) Construct a prediction model, which consists of two gated recurrent units and a dense recurrent network. The parameters for constructing the prediction model are input shape, gated recurrent unit size, regularization technique, optimizer selection, and loss function. c) Train the model using the training set data to obtain a trained model. d) Evaluate the model, which includes evaluating the performance of the trained model on the test set using root mean square error and mean absolute error. Based on the evaluation results, optimize the model to obtain an optimized model. The optimization mainly involves adjusting parameters. e) Use the optimized model to predict the data for the next time interval to obtain the predicted value.

[0018] The specific implementation of the early warning includes, based on the set early warning value and the predicted value, if the predicted value exceeds the early warning value, an early warning is issued and the deformation is controlled by the deformation control method; if the predicted value does not exceed the early warning value, the status quo is maintained and the deformation control method is not required.

[0019] S104, Deformation Control Method: The deformation control method includes strengthening the support structure, adjusting the excavation sequence, and controlling drainage. Strengthening the support structure includes adding a support structure on the existing basis to ensure the stability of the foundation pit. Adjusting the excavation sequence includes adjusting the excavation sequence and slowing down the excavation depth to reduce the amount and rate of deformation. Controlling drainage includes strengthening the foundation pit drainage system to reduce the influence of groundwater and ultimately reduce deformation. Strengthening the foundation pit drainage system includes setting more drainage holes at the bottom of the foundation pit and setting more drainage ditches around the foundation pit to lower the water level.

[0020] In the above embodiments, the present invention discloses a support structure and its deformation control method for ultra-deep foundation pit excavation construction, including support structure design, deformation monitoring method, deformation monitoring and early warning scheme and deformation control method; the support structure and its deformation control method for ultra-deep foundation pit excavation construction proposed by the present invention has the advantages of high safety and construction efficiency, small impact on the surrounding environment and low cost.

[0021] The above descriptions are illustrative embodiments of the present invention and are not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for deformation control of support structures during ultra-deep foundation pit excavation, characterized in that, The method includes the following steps: 1) Support structure design; 2) Deformation monitoring methods; 3) Deformation monitoring and early warning scheme; 4) Deformation control methods; The support structure design includes two aspects: the design of horizontal support and the design of vertical support. The horizontal support design includes anchor cables, and the vertical support design includes foundation pit support piles. The foundation pit support piles are cast-in-place concrete piles. The deformation monitoring method includes measuring the changing parameters of the foundation pit support by arranging monitoring points for the support structure. The monitoring points are arranged at the pile top and around the foundation pit. Depending on the monitoring purpose, the monitoring points are divided into surface settlement monitoring points, horizontal displacement monitoring points of the support piles, vertical displacement monitoring points of the support piles, and foundation pit water level monitoring points. The deformation monitoring and early warning scheme includes setting early warning values, acquiring predicted values, and implementing the early warning. Setting early warning values ​​involves setting early warning values ​​for the daily and total deformation at each monitoring point. Acquiring predicted values ​​involves using a prediction model to learn from historical data at each monitoring point to obtain predicted values ​​for the next time interval. The method for constructing the prediction model is as follows: a) Data preparation: collecting data from monitoring points, imputing missing values ​​using mean imputation, adjusting the data to a time-displacement format, and dividing the first 80% of the data into a training set and the last 20% into a test set; b) Constructing the prediction model... The prediction model consists of two gated recurrent units and a dense recurrent network. The parameters for constructing the prediction model are input shape, gated recurrent unit size, regularization technique, optimizer selection, and loss function. c) Training the model: The model is trained using training set data to obtain a trained model. d) Evaluating the model: The evaluation model includes evaluating the performance of the trained model on the test set using root mean square error and mean absolute error. Based on the evaluation results, the model is optimized to obtain an optimized model. The optimization mainly involves adjusting parameters. e) Using the optimized model, the model is used to predict the data for the next time interval to obtain the predicted value. The deformation monitoring and early warning scheme also includes the specific implementation of the early warning, which includes issuing an early warning based on a pre-set early warning value and a predicted value, and using a deformation control method to control the deformation if the predicted value exceeds the early warning value; if the predicted value does not exceed the early warning value, the status quo is maintained and no deformation control method is required. The deformation control method includes strengthening the support structure, adjusting the excavation sequence, and controlling drainage. Strengthening the support structure includes adding support structures on the existing basis to ensure the stability of the foundation pit. Adjusting the excavation sequence includes adjusting the excavation sequence and slowing down the excavation depth to reduce the amount and rate of deformation. Controlling drainage includes strengthening the foundation pit drainage system to reduce the impact of groundwater and ultimately reduce deformation. Strengthening the foundation pit drainage system includes setting more drainage holes at the bottom of the foundation pit and setting more drainage ditches around the foundation pit to lower the water level.

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