Method for predicting pipe jacking construction ground subsidence under complex geological conditions

Abstract

The invention discloses a complex geological condition pipe-jacking construction ground subsidence prediction method, which comprises the following steps: step 1, obtaining ground height, meteorological hydrology, geological structure and vegetation coverage data on a pipe-jacking path, and collecting the obtained ground height, meteorological hydrology, geological structure and vegetation coverage data; 2, after it is judged that the ground height, meteorological hydrology, geologic structure and vegetation coverage data obtained in the step 1 are ensured to be correct, the data are converted into a CSV data format in a unified mode; 3, superposing ground height, meteorological hydrology, geologic structure and vegetation coverage data of different sources on a map by using a ground surface information system to form a comprehensive ground surface information map layer; 4, constructing a ground surface model based on the data, and performing settlement trend prediction by using a grey prediction model technology; and 5, presenting the prediction result in the step 4 in a chart or map form. The method has the advantages that the area where sedimentation occurs in the pipe jacking construction process can be predicted, and the like.

Description

Technical Field

[0001] The invention relates to a pipe jacking construction method, in particular to a method for predicting ground subsidence during pipe jacking construction under complex geological conditions. Background Art

[0002] In recent years, pipe jacking construction has made considerable achievements in technology, mechanical properties and forms. However, with the development of pipe jacking construction, there are many unavoidable problems in the process of pipe jacking construction, which will cause adverse consequences such as surface settlement and underground cavities, thus affecting the surrounding pipelines, buildings (structures), and traffic roads.

[0003] During pipe jacking construction, there will be complex geological conditions such as easy collapse and water, sand and mud gushing, and corresponding measures should be taken. During pipe jacking construction, such unfavorable geological conditions are prone to collapse, causing surface subsidence, and are prone to risks such as water, sand and mud gushing. In addition, the bearing capacity of the stratum is low and it cannot be used as the bearing layer of the pipeline foundation without treatment.

[0004] Existing methods of pipe jacking construction include: for example, Chinese patent document (CN112797227B) "Complex Environment Ultra-Long Distance Pipe Jacking Structure and Construction Method", which discloses the relevant equipment required for pipe jacking construction, and opens a working well in the middle of the construction route, and then opens receiving wells on both sides of the working well. During pipe jacking construction, pipe jacking construction is carried out from the working well to both sides simultaneously; however, it does not provide how to monitor ground subsidence during the construction process.

[0005] For another example, a Chinese patent document (CN109594990B) discloses a large-section pipe jacking construction method in a complex stratum, which discloses: before jacking construction, the geological survey report is analyzed, and for strata that are soft on the top and hard on the bottom, the upper fluid soil layer is reinforced in advance, and the quicksand layer or silt layer is consolidated. However, the quicksand layer or silt layer is a soil structure that causes surface subsidence.

[0006] Therefore, in view of the defects of the existing technology, it is necessary to develop a method for predicting ground subsidence in pipe jacking construction under complex geological conditions. Summary of the invention

[0007] The purpose of the present invention is to provide a method for predicting ground subsidence in pipe jacking construction under complex geological conditions in view of the defects of the prior art.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical scheme is adopted:

[0009] A method for predicting ground subsidence in pipe jacking construction under complex geological conditions, the method comprising the following steps:

[0010] Step 1: Obtain the ground height, meteorological and hydrological data, geological structure and vegetation coverage data on the pipe jacking path, and collect the obtained ground height, meteorological and hydrological data, geological structure and vegetation coverage data;

[0011] Step 2: After ensuring that the ground height, meteorological and hydrological, geological structure, and vegetation coverage data obtained in step 1 are correct, convert the data into CSV data format;

[0012] Step 3: Use the GIS to overlay the ground height, meteorological and hydrological, geological structure, and vegetation cover data from different sources on a map to form a comprehensive surface information layer;

[0013] Step 4: Based on the above data, construct a surface model and use the grey prediction model technology to predict the subsidence trend;

[0014] Step 5: Present the prediction results of step 4 in the form of a chart or map.

[0015] Furthermore, as a further improvement of the present invention, in step 4, the creep tangent angle is used to divide the level of ground settlement;

[0016] Normal level: the land subsidence rate is less than 0.1 mm / day and the tangent angle is less than 1°;

[0017] Slight warning level: the ground subsidence rate is between 0.1 mm / day and 1 mm / day, and the tangent angle is between 1° and 3°;

[0018] Moderate warning level: the ground subsidence rate is between 1 mm / day and 5 mm / day, and the tangent angle is between 3° and 6°;

[0019] Severe warning level: ground subsidence rate is greater than 5 mm / day, and the tangent angle is greater than 6°.

[0020] Furthermore, as a further improvement of the present invention, when ground subsidence is predicted in step 4, an alarm can be sounded and an alarm text message or email can be sent out, or a ground subsidence alarm phone call can be dialed.

[0021] Furthermore, as a further improvement of the present invention, in step one, satellite remote sensing is used to obtain meteorological, hydrological and vegetation coverage data.

[0022] Furthermore, as a further improvement of the present invention, in step one, geological structure data is obtained through a geological information system.

[0023] Furthermore, as a further improvement of the present invention, the step four also includes surface settlement treatment measures, and the surface settlement treatment measures include any one of pre-grouting reinforcement, deep mixing piles or high-pressure rotary jet piles.

[0024] Furthermore, as a further improvement of the present invention, settlement trend prediction is performed based on the grey prediction model technology, and the location where settlement is about to occur is known, and pre-grouting reinforcement is performed on the location, and the pre-grouting reinforcement is radial grouting that expands 2 to 3.5 meters outward along the jacking path.

[0025] Furthermore, as a further improvement of the present invention, the grouting measures include: the depth of the grouting slurry range is: 10-20cm; the grouting pressure is: 250-350Kpa; the grouting hole spacing L is: R≤L≤2R, R is the radius of the grouting pipe.

[0026] The present invention has the following improvements over the prior art:

[0027] 1. The present invention reduces the impact of external soil on the surrounding ground, achieves ground settlement under complex geological conditions less than 60% of the standard limit, and ensures the stability and safety of the ground and surrounding buildings (structures). The present invention is based on the ground settlement deformation mechanism and instability failure mechanics model of ground settlement under complex geological conditions and groundwater influence, and constructs a ground settlement analysis system.

[0028] 2. The present invention obtains on-site geological data and on-site surface deformation monitoring data, so that accurate and detailed on-site geological data, accurate mechanical parameter values ​​and surface deformation monitoring data can not only provide basic data for surface deformation prediction, long-term stability evaluation, and treatment measure effect evaluation during pipe jacking construction, but also provide real-time feedback on the construction situation, guide construction and optimize construction technology.

[0029] 3. The present invention can evaluate and analyze the treatment measures for controlling surface subsidence at different times, avoid the possible surface subsidence during the pipe jacking process, and take corresponding treatment measures in time.

[0030] 4. The present invention can monitor the excavation working conditions in real time, predict settlement in advance, and then take corresponding reinforcement measures to avoid collapse during excavation. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present application.

[0032] Embodiment 1:

[0033] This embodiment is a method for predicting ground settlement during pipe jacking construction under complex geological conditions, and the method comprises the following steps:

[0034] Step 1: Obtain the ground height, meteorological and hydrological data, geological structure and vegetation coverage data on the pipe jacking path, and collect the ground height, meteorological and hydrological data, geological structure and vegetation coverage data; satellite remote sensing can be used to obtain meteorological and hydrological data and vegetation coverage data; geological structure data can be obtained through the geological information system.

[0035] Step 2: After ensuring that the ground height, meteorological and hydrological, geological structure, and vegetation coverage data obtained in step 1 are correct, convert the data into CSV data format.

[0036] Step 3: Use the GIS to overlay ground height, meteorological and hydrological, geological structure, and vegetation cover data from different sources on a map to form a comprehensive surface information layer.

[0037] Step 4: Based on the data from step 2, construct a surface model and use the grey prediction model technology to predict the subsidence trend.

[0038] Step 5: Present the prediction results of step 4 in the form of a chart or map.

[0039] Land subsidence: The surface information system GIS can predict land subsidence from spatial and temporal perspectives by integrating land subsidence simulation and prediction methods and combining GPS and remote sensing data.

[0040] Meteorology and hydrology: GIS can process data related to meteorology and hydrology, such as rainfall, temperature, humidity, etc., which are of great significance for predicting natural disasters such as floods and droughts. Through the spatial analysis function of GIS, the distribution pattern and change trend of meteorological and hydrological data can be studied, and meteorological and hydrological data can be provided for the pipe jacking construction route of the present invention.

[0041] Geological structure: GIS also plays an important role in geological structure research. By processing data related to geological structure, such as earthquake activity and rock layer structure, it helps to understand geological movements and potential geological disaster risks. The three-dimensional modeling and visualization functions of GIS can intuitively display the complexity and dynamic changes of geological structures on the pipe jacking construction route of the present invention.

[0042] Vegetation coverage: In terms of environmental protection, GIS software can help evaluate indicators such as vegetation coverage and water pollution, providing a scientific basis for environmental protection decisions. By processing vegetation coverage data, the changing trend of vegetation distribution can be analyzed, and vegetation coverage data can be provided for the pipe jacking construction route of the present invention.

[0043] The present invention can be used to predict ground settlement during pipe jacking construction. Specifically, the frictional resistance, head pressure and soil resistance of the pipe jacking are brought into the surface model of the present invention, and the ground settlement on the pipe jacking construction route can be predicted through the surface model. It is convenient to pre-reinforce the location where ground settlement may occur before construction.

[0044] The present invention can also be used to monitor ground subsidence during pipe jacking construction. Specifically, the ground height, meteorological and hydrological data, geological structure and vegetation coverage data on the pipe jacking construction route are first obtained as raw data. During the construction process, the ground height, meteorological and hydrological data, geological structure and vegetation coverage data on the pipe jacking construction route can be obtained in real time through satellite remote sensing technology and the surface information system, and brought into the surface model. The ground subsidence trend on the pipe jacking construction route is monitored in real time through the surface model, and the points where ground subsidence occurs on the pipe jacking construction route are obtained, and then corresponding surface subsidence treatment measures are taken.

[0045] In order to know the grade of ground subsidence, the creep tangent angle is used to classify the grade of ground subsidence in step 4.

[0046] Normal level: The ground settlement rate is less than 0.1 mm / day and the tangent angle is less than 1°.

[0047] Mild warning level: The ground subsidence rate is between 0.1mm / day and 1mm / day, and the tangent angle is between 1° and 3°.

[0048] Moderate warning level: The ground subsidence rate is between 1 mm / day and 5 mm / day, and the tangent angle is between 3° and 6°.

[0049] Severe warning level: ground subsidence rate is greater than 5 mm / day, and the tangent angle is greater than 6°.

[0050] In order to facilitate rapid knowledge of predicted ground subsidence, when predicted ground subsidence is detected in step 4, an alarm can be sounded and an alarm text message or email can be sent out, or a ground subsidence alarm phone number can be dialed.

[0051] When surface settlement is predicted to occur, surface settlement treatment measures can be taken in the area where settlement is about to occur. The surface settlement treatment measures include any one of pre-grouting reinforcement, deep mixing piles or high-pressure rotary jet spraying piles.

[0052] The combination groups include: pre-grouting reinforcement, deep mixing piles, high-pressure rotary jet piles, pre-grouting reinforcement and deep mixing piles, pre-grouting reinforcement and high-pressure rotary jet piles, deep mixing piles and high-pressure rotary jet piles, and also include a combination of pre-grouting reinforcement, deep mixing piles and high-pressure rotary jet piles.

[0053] When pre-grouting is used to control ground settlement, radial grouting is performed along the pipe jacking construction route, expanding 2 to 3.5 meters outward to enhance ground strength and prevent ground settlement.

[0054] Deep mixing piles are made by using deep mixing machinery to forcefully mix soft soil or sand with a curing agent in the foundation, thereby hardening the soft foundation and improving the foundation strength.

[0055] High-pressure jet grouting piles use high-pressure rotating nozzles to spray cement slurry into the soil layer and mix it with the soil to form a continuous overlapping cement reinforcement body. The construction occupies a small area, has low vibration and low noise, but it is easy to pollute the environment and has a high cost. It is not suitable for special soils that cannot solidify the sprayed slurry.

[0056] In some embodiments of the present disclosure, the settlement trend is predicted according to the grey prediction model technology, and the location where settlement is about to occur is known, and then pre-grouting reinforcement is performed on the location, and the pre-grouting reinforcement is radial grouting along the top pipe path expanding 2 to 3.5 meters. The depth of the grouting slurry range is: 10 to 20 cm; the grouting pressure is: 250 to 350 Kpa; the grouting hole spacing L is: R≤L≤2R, R is the radius of the grouting pipe.

[0057] It can be understood that one distribution mode of the grouting holes is: along the longitudinal direction of the pipe segment, the grouting holes are distributed on both sides and the top thereof, and during grouting, the slurry wraps the outer side surface of the pipe segment.

[0058] When grouting, thixotropic mud is generally used. Thixotropic mud is a mixed liquid that contacts the soil under pressure and penetrates into the soil layer, slowly spreads out, and forms a whole with the surrounding soil. As the amount of infiltration increases, the soil and mud will form a dense permeable block. At the same time, under the action of the mud pressure, the blocks are tightly combined, so that a stable mud sleeve composed of mud and soil is formed around the pipeline. Thixotropic mud has fluidity during transportation and injection, and is a gel-like liquid. It changes the dry friction between the outer wall of the pipeline and the soil layer into wet friction, reducing friction. After a certain period of standing, the mud solidifies into a gel, which can support the soil, balance the soil pressure, make the soil around the pipeline stable, and prevent ground subsidence.

[0059] The speed of pipe jacking can be 10mm~200mm / min, but it is not limited to this. According to actual needs, the adjustable speed is: 10mm / min, 20mm / min, 30mm / min, 50mm / min, 100mm / min, 105mm / min, 150mm / min, 180mm / min or 200mm / min, etc. It can ensure stable pipe jacking and reduce damage to the soil layer around the pipe jacking, thereby reducing the risk of ground subsidence.

[0060] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A method for predicting ground subsidence in pipe jacking construction under complex geological conditions, characterized in that: The method comprises the following steps: Step 1: Obtain the ground height, meteorological and hydrological data, geological structure and vegetation coverage data on the pipe jacking path, and unify the collected ground subsidence, meteorological and hydrological data, geological structure and vegetation coverage data; Step 2: After ensuring that the ground height, meteorological and hydrological, geological structure, and vegetation coverage data obtained in step 1 are correct, convert the data into CSV data format; Step 3: Use the surface information system to overlay the ground height, meteorological and hydrological, geological structure, and vegetation cover data from different sources on a map to form a comprehensive surface information layer; Step 4: Based on the above data, construct a surface model and use the grey prediction model technology to predict the subsidence trend; Step 5: Present the prediction results of step 4 in the form of a chart or map.

2. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 1 is characterized by: In the step 4, the creep tangent angle is used to classify the ground settlement level; Normal level: the land subsidence rate is less than 0.1 mm / day and the tangent angle is less than 1°; Slight warning level: the ground subsidence rate is between 0.1 mm / day and 1 mm / day, and the tangent angle is between 1° and 3°; Moderate warning level: the ground subsidence rate is between 1 mm / day and 5 mm / day, and the tangent angle is between 3° and 6°; Severe warning level: ground subsidence rate is greater than 5 mm / day, and the tangent angle is greater than 6°.

3. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 2, characterized in that: When ground subsidence is predicted in step 4, an alarm can be sounded and an alarm text message or email can be sent out, or a ground subsidence alarm phone number can be dialed.

4. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 1, characterized in that: In the step 1, satellite remote sensing is used to obtain meteorological, hydrological and vegetation coverage data.

5. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 1 is characterized by: In the step 1, geological structure data is obtained through a geological information system.

6. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 1, characterized in that: The step four also includes surface settlement treatment measures, which include any one of pre-grouting reinforcement, deep mixing piles or high-pressure rotary jet spraying piles.

7. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 1, characterized in that: The settlement trend is predicted based on the grey prediction model technology, and the location where settlement is about to occur is known, and then pre-grouting reinforcement is performed on the location. The pre-grouting reinforcement is radial grouting that expands 2 to 3.5 meters outward along the jacking path.

8. The method for predicting ground subsidence in pipe jacking construction under complex geological conditions according to claim 6 is characterized by: The depth of the grouting slurry range is: 10 to 20 cm; Grouting pressure: 250~350Kpa; The hole spacing L for grouting is: R≤L≤2R, where R is the radius of the grouting pipe.