A foundation pit partition excavation and supporting method based on protection of existing pipeline safety

Abstract

The application discloses a kind of based on the safety of existing pipeline partition excavation and supporting method of foundation pit, applicable to the field of foundation pit construction, including determining pipeline position and protection range, making foundation pit partition excavation scheme and pipeline displacement monitoring scheme, start digging, foundation pit supporting and complete excavation;The kind of based on the safety of existing pipeline partition excavation and supporting method of foundation pit proposed by the application can effectively protect the safety of existing pipeline, realize the organic combination of foundation pit excavation and pipeline protection, and can be applied to the field of foundation pit construction.

Description

TECHNICAL FIELD

[0001] The application relates to a foundation pit excavation method, in particular to a foundation pit partitioned excavation and supporting method based on protection of existing pipeline safety. BACKGROUND

[0002] With the continuous advancement of urbanization, various infrastructure construction projects are also increasing. Among them, pipelines are an indispensable part of the city, which are used to transport water, gas, oil and other substances, providing necessary support for the normal operation of the city. However, during the urban construction process, it is often necessary to excavate the ground for various engineering construction, such as building foundation, highway, bridge, subway, etc. These construction activities may damage the existing pipelines, leading to safety accidents. Therefore, how to protect the safety of existing pipelines has become a problem to be solved.

[0003] In the traditional excavation construction, a deep foundation pit excavation method is usually adopted, that is, a large area of earthwork is first excavated, and then the foundation construction is carried out in the excavated pit. Although this method is efficient, it also has great safety hazards, especially when the pipeline crosses the foundation pit, which is more likely to be affected. For example, during the excavation of the foundation pit, the pipeline may be deformed by external force, causing pipeline rupture or loose connection; in addition, the construction of the foundation pit supporting structure may also cause extrusion or displacement of the pipeline, resulting in permanent deformation or damage of the pipeline. In order to avoid these problems, an effective method is needed to control and protect the foundation pit excavation and supporting.

[0004] At present, many solutions have been proposed to solve the safety problem of pipelines. For example, the direction of foundation pit excavation can be changed to avoid the area where the pipeline is located; or local excavation, step-by-step backfilling and other methods can be adopted to reduce the stress range of the pipeline. In addition, reinforced supporting structures can be set up around the pipeline, or light and heavy supports can be used to ensure the stability of the pipeline. However, these methods have certain limitations and cannot fully meet the actual engineering needs. SUMMARY

[0005] The purpose of the present application is to provide a foundation pit partitioned excavation and supporting method based on protection of existing pipeline safety, which can effectively protect the safety of existing pipelines and realize the organic combination of foundation pit excavation and pipeline protection.

[0006] The purpose of the present application can be achieved by adopting the following technical solutions:

[0007] S101, determining the pipeline position and protection range: the determination of the pipeline position and protection range includes determining the type, depth and position of the pipeline according to the geological survey data and pipeline drawings, and determining the pipeline protection range, the pipeline protection range is divided into a horizontal range d hand vertical range d v , the calculation formula is formula (1) and formula (2),

[0008] d h =D+f1+f2+f s1 (1)

[0009] d v = d p + D + f3+ f s2 (2)

[0010] In the formula, D is the diameter of the pipeline, f1 is the horizontal expansion distance required for construction and maintenance, f2 is the horizontal extension distance required for construction maintenance support f2 is the horizontal extension distance required for construction maintenance support , f s1 is the horizontal safety margin, which is determined in combination with local laws and regulations and engineering experience, d p is the distance from the top surface of the pipeline to the ground, f3 is the vertical expansion range required for construction and maintenance, f s2 is the vertical safety margin, which is determined in combination with local laws and regulations and engineering experience.

[0011] S102, a foundation pit partition excavation scheme and a pipeline displacement monitoring scheme are formulated: the foundation pit partition excavation scheme and the pipeline displacement monitoring scheme are formulated, including designing a reasonable foundation pit partition excavation scheme according to the calculation results of the pipeline protection range, and combining the construction conditions on site and the characteristics of the pipeline, the range of excavation is controlled through partition excavation to avoid affecting the pipeline;

[0012] The foundation pit partition excavation scheme and the pipeline displacement monitoring scheme also include formulating a pipeline displacement monitoring scheme, setting displacement monitoring points at the pipeline, monitoring the displacement of the pipeline during the excavation construction process, and predicting the displacement of the pipeline according to a displacement prediction method, and if the predicted value reaches a warning value, timely warning is given to feedback the construction and timely adjustment, the warning value is formulated according to local relevant regulations, pipeline properties and engineering experience, the warning value includes two aspects, displacement rate warning value and maximum displacement warning value, the main steps of the displacement prediction method are: a) collecting historical displacement time series data to obtain a historical displacement time series data set, b) normalizing the data, the normalization method used is the maximum and minimum value method, c) dividing the data set into a training set and a test set according to a 7:3 ratio, the first 70% of the data constitutes the training set, and the last 30% of the data is used as the test set, d) model building, the prediction model is built using a long short-term memory neural network, the prediction model optimization algorithm uses the Adam algorithm, the prediction model activation function uses the hyperbolic tangent function, and the prediction model uses mean square error as the loss function, e) training the prediction model using the training set data, f) testing the prediction model using the test set data, and if the requirements are met, the prediction model is obtained, otherwise, return to step c) to re-perform;

[0013] S103, start excavating: the start excavating includes excavating the foundation pit according to the foundation pit partition excavation scheme, monitoring the pipeline displacement in time according to the pipeline displacement monitoring method, and predicting the pipeline displacement according to the displacement prediction model, and issuing a warning in time if the warning value is reached, so as to adjust the construction;

[0014] S104, foundation pit support construction: the foundation pit support construction includes supporting and constructing the foundation pit partition in time after excavation according to the foundation pit partition excavation scheme;

[0015] S105, complete excavating: the complete excavating includes completing all construction steps according to the foundation pit partition excavation scheme.

[0016] Further, in the above S102, the maximum minimum value method calculation formula is formula (1),

[0017] In the formula, X is the normalized model input data, x is the original data, x min is the minimum value of the original data, and x max is the maximum value of the original data.

[0018] Further, in the above S102, the loss function calculation formula is formula (2),

[0019] In the formula, LOSS is the loss function, n is the number of prediction results, is the true value, and y i is the predicted value.

[0020] The beneficial effects of the present application are:

[0021] Compared with the prior art, the present application is a foundation pit partition excavation and support method based on protecting the safety of existing pipelines, which can effectively protect the safety of existing pipelines and realize the organic combination of foundation pit excavation and pipeline protection. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 : is a flowchart of the foundation pit partition excavation and support method based on protecting the safety of existing pipelines. DETAILED DESCRIPTION

[0023] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application are described with reference to the accompanying drawings.

[0024] As Figure 1 shown, a foundation pit partition excavation and support method based on protecting the safety of existing pipelines is proposed, and the flowchart includes the following contents.

[0025] S101, determining pipeline position and protection range: the determination of pipeline position and protection range includes determining the type, depth and position of the pipeline according to geological survey data and pipeline drawings, determining the pipeline protection range, and the pipeline protection range is divided into horizontal range d h and vertical range d v , the calculation formula is formula (1) and formula (2),

[0026] d h =D+f1+f2+f s1 (1)

[0027] d v = d p + D + f3+ f s2 (2)

[0028] In the formula, D is the diameter of the pipeline, f1 is the horizontal expansion distance required for construction and maintenance, f2 is the horizontal extension distance required for construction maintenance support f2 is the horizontal extension distance required for construction maintenance support , f s1 is the horizontal safety margin, which is determined in combination with local laws and regulations and engineering experience, d p is the distance from the top surface of the pipeline to the ground, f3 is the vertical expansion range required for construction and maintenance, f s2 is the vertical safety margin, which is determined in combination with local laws and regulations and engineering experience;

[0029] S102, making a foundation pit partition excavation scheme and a pipeline displacement monitoring scheme: the making of a foundation pit partition excavation scheme and a pipeline displacement monitoring scheme includes designing a reasonable foundation pit partition excavation scheme according to the calculation results of the pipeline protection range, and combining the construction conditions on site and the characteristics of the pipeline, and controlling the excavation range by partition excavation to avoid affecting the pipeline;

[0030] The making of the foundation pit partition excavation scheme and the pipeline displacement monitoring scheme further comprises making the pipeline displacement monitoring scheme, setting displacement monitoring points at the pipeline, monitoring the pipeline displacement during the excavation construction process, and predicting the pipeline displacement according to a displacement prediction method, if the predicted value reaches a warning value, timely warning to feedback the construction, and timely adjusting, the warning value is made according to the local relevant regulations, the pipeline nature and the engineering experience, the warning value includes two aspects, respectively, the displacement rate warning value and the maximum displacement warning value, the main steps of the displacement prediction method are: a) collecting historical displacement time series data to obtain a historical displacement time series data set, b) normalizing the data, the normalization method used is the maximum and minimum value method, c) dividing the data set into a training set and a test set according to a 7:3 ratio, the first 70% of the data constitutes the training set, and the last 30% of the data is used as the test set, d) model building, the model building uses a long short-term memory neural network to build a prediction model, the prediction model optimization algorithm uses the Adam algorithm, the prediction model activation function uses the hyperbolic tangent function, and the prediction model uses the mean square error as the loss function, e) training the prediction model using the training set data, f) testing the prediction model using the test set data, and if the requirements are met, the prediction model is obtained, otherwise, return to step c) to re-perform; further, the maximum and minimum value method calculation formula is formula (1),

[0031] In the formula, X is the normalized model input data, x is the original data, x min is the minimum value of the original data, and x max is the maximum value of the original data.

[0032] Further, the loss function calculation formula is formula (2),

[0033] In the formula, LOSS is the loss function, n is the number of prediction results, is the true value, and y i is the predicted value.

[0034] In the above embodiment, the present application discloses a foundation pit partition excavation and support method based on protecting existing pipeline safety, which mainly comprises determining the pipeline position and protection range, making the foundation pit partition excavation scheme and the pipeline displacement monitoring scheme, starting excavation, foundation pit support construction and completing excavation; the foundation pit partition excavation and support method based on protecting existing pipeline safety can effectively protect the safety of existing pipelines, realize the organic combination of foundation pit excavation and pipeline protection, and can be applied to the field of foundation pit construction.

[0035] The above description is only the illustrative embodiment of the present application, and is not intended to limit the scope of the present application. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present application shall fall within the scope of the present application.

Claims

1. A method for zonal excavation and support of foundation pits based on protecting the safety of existing pipelines, characterized in that, The method includes the following steps: 1) Determine the location of the pipeline and the protection area; 2) Develop a zoned excavation plan for the foundation pit and a pipeline displacement monitoring plan; 3) Begin digging; 4) Construction of foundation pit support; 5) Complete the excavation; Determining the pipeline location and protection area includes, based on geological survey data and pipeline drawings, determining the type, depth, and location of the pipeline, and defining the pipeline protection area, which is divided into a lateral range d. h and vertical range d v The calculation formulas are equation (1) and equation (2). d h =D+f1+f2+f s1 (1) d v =d p +D+f3+f s2 (2) In the formula, D is the pipe diameter, and f1 is the horizontal expansion distance required for construction and maintenance. f2 is for construction. Horizontal expansion distance required for maintenance support f s1 To provide a horizontal safety margin, d was determined based on local laws and regulations and engineering experience. p f is the distance from the top of the pipe to the ground, f3 is the vertical expansion range required for construction and maintenance, f s2 The vertical safety margin was determined based on local laws and regulations and engineering experience. The formulation of the foundation pit zoning excavation plan and pipeline displacement monitoring plan includes designing a reasonable foundation pit zoning excavation plan based on the calculation results of the pipeline protection range and in combination with the on-site construction conditions and pipeline characteristics. The zoning excavation controls the excavation range and avoids impact on the pipeline. The formulation of the foundation pit zoning excavation plan and pipeline displacement monitoring plan also includes formulating a pipeline displacement monitoring plan, setting displacement monitoring points at the pipeline locations, monitoring pipeline displacement during excavation, and predicting pipeline displacement using a displacement prediction method. If the predicted value reaches the warning value, a warning is issued promptly to provide feedback for construction and timely adjustments. The warning value is formulated based on local regulations, pipeline characteristics, and engineering experience. The warning value includes two aspects: a displacement rate warning value and a maximum displacement warning value. The main steps of the displacement prediction method are: a) collecting historical displacement change time-series data to obtain a historical displacement time-series data set; b) processing the data... The normalization process uses the minimum-maximum method. c) The dataset is divided into a training set and a test set in a 7:3 ratio, with the first 70% of the data forming the training set and the last 30% forming the test set. d) Model construction uses a long short-term memory neural network to build a prediction model. The prediction model optimization algorithm uses the Adam algorithm, the prediction model activation function uses the hyperbolic tangent function, and the prediction model uses the mean squared error as the loss function. e) The prediction model is trained using the training set data. f) The prediction model is tested using the test set data. If it meets the requirements, the prediction model is obtained; otherwise, return to step c and repeat. The commencement of excavation includes excavating the foundation pit in sections according to the foundation pit zoning excavation plan, monitoring pipeline displacement in a timely manner according to the pipeline displacement monitoring method, predicting pipeline displacement according to the displacement prediction model, and issuing an early warning in a timely manner if the requirements of the early warning value are met, so as to facilitate construction adjustments. The foundation pit support construction includes timely support construction for the foundation pit sections after excavation is completed, according to the foundation pit section excavation plan; The completion of excavation includes completing all construction steps according to the pit zoning excavation plan.

2. The method for zonal excavation and support of foundation pits based on protecting the safety of existing pipelines according to claim 1, characterized in that: In step 2), the maximum and minimum value method calculation formula is equation (1). In the formula, X represents the normalized model input data, x represents the original data, and x0 represents the input data. min x is the minimum value of the original data. max This represents the maximum value of the original data.

3. The method for zonal excavation and support of foundation pits based on protecting the safety of existing pipelines according to claim 1, characterized in that: In step 2), the loss function is calculated using equation (2). In the formula, LOSS is the loss function, and n is the number of prediction results. For the true value, y i These are predicted values.

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