Automatic monitoring system for soil pressure balance in shield construction

Abstract

The invention relates to the technical field of shield construction, in particular to an automatic monitoring system for soil pressure balance in shield construction. Comprising a rainfall module, a detection module and an operation analysis module and is used for judging whether the soil body is balanced and stable or not according to an integral value; if yes, adjusting the power of a dewatering well water pump according to the comparison result of the absolute value of the difference value of the actual soil temperature and the temperature obtained through the soil temperature gradient and the threshold value and whether dewatering exists or not, or adjusting the detection period, or optimizing the construction parameters of the shield tunneling machine. According to the invention, integration is carried out on the soil pressure in the monitoring period, and settlement risk assessment is carried out in the preparation stage before settlement, so that the timeliness of data in the soil pressure balance monitoring process is improved; and meanwhile, parameters influencing the evaluation result are adjusted according to the evaluation result, so that the accuracy of soil pressure balance monitoring is improved.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to an automatic monitoring system for soil pressure balance in shield construction. Background Art

[0002] During the advancement of the earth pressure balance shield machine, the soil in the stratum is cut down by the rotation of the cutting disc at the front end of the shield machine and enters the sealed soil chamber behind the disc. Then the screw conveyor transports the slag to the surface. When the sealed soil chamber is full of soil, its passive earth pressure is basically balanced with the earth pressure and water pressure on the excavation surface. At this time, the excavation surface and the shield surface are in a balanced state (i.e. stable state). However, most of the surface settlement and pipeline deformation warning systems caused by shield machine excavation are complex in structure and relatively slow in information feedback. They cannot guarantee real-time dynamic monitoring and make relevant adjustments in time according to the monitoring data to guide shield construction.

[0003] Chinese patent publication number CN 116988806A discloses an earth pressure balance model shield machine capable of realizing multi-position earth pressure state monitoring, comprising: a shield frame, a cutting system, a jacking system, an excavation system and an earth pressure monitoring system. The earth pressure balance model shield machine capable of realizing multi-position earth pressure state monitoring has the following problems: the construction parameters can only be adjusted according to whether the earth pressure is unbalanced, and the settlement caused by earth pressure fluctuation is ignored, and it is impossible to ensure real-time dynamic monitoring and make relevant adjustments in time according to the monitoring data to guide the shield construction, thereby failing to ensure the timeliness and accuracy of the construction parameter adjustment during the construction process. Summary of the invention

[0004] To this end, the present invention provides an automatic monitoring system for soil pressure balance during shield construction, so as to overcome the problem in the prior art that the accuracy and timeliness of construction parameter adjustment during the construction process cannot be guaranteed.

[0005] To achieve the above objectives, the automatic monitoring system for earth pressure balance during shield construction includes:

[0006] Shield machine;

[0007] A dewatering module, comprising a water collection well for lowering the groundwater level and a pumping machine arranged in the water collection well for pumping water;

[0008] The detection module includes an earth pressure monitoring unit for monitoring earth pressure, a temperature detection unit provided in the shield machine for detecting the actual temperature of the soil during the construction of the shield machine, and a soil detection unit for detecting soil settlement parameters;

[0009] The operation and analysis module is connected to the precipitation module and the detection module respectively, and is used to integrate the area formed by the average soil pressure and the soil pressure change curve, so as to judge whether the soil balance is stable according to the integral value. If the judgment result is unstable, the absolute value of the difference between the actual soil temperature during the construction of the shield machine and the temperature obtained according to the soil temperature gradient is compared with the threshold value. According to the comparison result and whether precipitation occurs, the power of the precipitation well pump is adjusted, the detection period is adjusted, or the construction parameters of the shield machine are optimized.

[0010] Furthermore, the operation and analysis module determines whether the soil is balanced and stable according to the integral value, wherein:

[0011] If the integral value is less than or equal to the integral critical value, it is determined that the soil balance is stable.

[0012] If the integral value is greater than a preset integral critical value, the soil is determined to be unstable, and the cause of the soil instability is determined based on the temperature deviation value;

[0013] Furthermore, within a single detection cycle, the calculation and analysis module draws a real-time soil pressure curve based on the monitoring data of the soil pressure monitoring unit and obtains the average value of the soil pressure within the detection cycle, integrates the areas formed by the starting point and end point of the detection cycle, the soil pressure curve, and the average value of the soil pressure, and sums the obtained integral values ​​to calculate the integral value.

[0014] Furthermore, the cause of soil instability is determined based on the temperature deviation value.

[0015] If the temperature deviation value is greater than the threshold, it is determined that the cause is the fluctuation of the groundwater level, and measures are taken to increase the pumping power of the dewatering well at the construction site;

[0016] If the temperature deviation value is less than or equal to the threshold, the cause is determined according to the precipitation situation;

[0017] The temperature deviation value is the absolute value of the difference between the standard temperature and the actual temperature.

[0018] Furthermore, the operation and analysis module establishes a soil temperature gradient for the current construction area according to the surface temperature and soil thermal conductivity, determines the temperature of the soil under normal conditions at the construction depth according to the temperature gradient and the current construction depth of the shield machine, and records it as the standard temperature.

[0019] Further, in response to determining the cause according to the precipitation condition,

[0020] If precipitation occurs and the precipitation is greater than the precipitation threshold, it is determined that the cause of the fluctuation is surface precipitation, and the monitoring period is reduced to a corresponding value according to the precipitation difference;

[0021] If no precipitation occurs or the precipitation is less than or equal to the precipitation threshold, it is determined that there is a problem with the current construction parameters and a construction plan adjustment notice is issued.

[0022] Furthermore, the precipitation threshold is determined by the operation and analysis module according to the soil properties and construction depth of the current construction area, that is, when the precipitation is less than a certain value, the impact on the moisture content of the soil at the current construction depth is less than one percent, and the precipitation value is determined as the precipitation threshold.

[0023] Further, the pumping power of the dewatering well at the construction site is determined according to the temperature standard deviation;

[0024] The temperature standard deviation is a difference between the temperature deviation value and the threshold value.

[0025] Further, the adjustment of the monitoring period is determined according to the precipitation difference;

[0026] The precipitation difference is the difference between the precipitation and the precipitation threshold.

[0027] Furthermore, after the detection period is adjusted, the preset integral threshold value needs to be adjusted accordingly.

[0028] Compared with the prior art, the beneficial effect of the present invention is that, in actual construction, the method for determining whether the earth pressure is in a balanced or unbalanced state is mostly to compare the measured earth pressure with a threshold value or to observe the settlement. Data abnormalities will only appear when settlement is about to occur, leaving construction personnel with a short reaction time. The continuous action of the shield machine cutter head will cause the earth pressure to fluctuate continuously. This fluctuation within the specified range of earth pressure balance will also affect the balance of the soil body. In this case, it is difficult to determine the cause and take timely countermeasures. The present invention integrates the real-time curve of earth pressure within the monitoring period, and determines the current construction depth and the properties of the soil on the construction route through a limited number of experiments to determine the critical value of the integration. This fluctuation requires a certain amount of time to act before settlement can occur, so that the settlement risk is evaluated in the preparation stage before settlement occurs, thereby increasing the timeliness of data in the process of earth pressure balance monitoring; at the same time, the parameters affecting the evaluation results are adjusted according to the evaluation results, thereby increasing the accuracy of earth pressure balance monitoring.

[0029] Specifically, another factor affecting soil balance is the influence of pore water in the soil. Since groundwater is in a relatively low temperature state all year round and the temperature remains basically unchanged, it is possible for the present invention to determine the reasons based on the impact of temperature on groundwater or surface precipitation or shield machine construction. At the same time, by detecting the soil properties at different depths, the soil temperature gradient is drawn, and the actual temperature can be obtained through simple measurement of the soil discharge, which is easy to implement in the actual construction process, making the data analysis process simple and the data timely and effective, thereby increasing the timeliness of soil pressure balance monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural block diagram of an automatic monitoring system for earth pressure balance in shield construction according to an embodiment of the present invention;

[0031] Figure 2 This is a flow chart of determining the cause of soil instability according to the temperature deviation value according to an embodiment of the present invention;

[0032] Figure 3 This is a flow chart of determining the cause of soil instability according to precipitation conditions according to an embodiment of the present invention;

[0033] Figure 4 This is a flow chart for determining the adjustment method selected in the embodiment of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] See also Figure 1 As shown, it is a structural block diagram of the automatic monitoring system for earth pressure balance in shield construction according to the present invention, including:

[0039] Shield machine;

[0040] A dewatering module, comprising a water collection well for lowering the groundwater level and a pumping machine arranged in the water collection well for pumping water;

[0041] The detection module includes an earth pressure monitoring unit for monitoring the earth pressure, a temperature detection unit provided in the shield machine for detecting the actual temperature of the soil during the construction of the shield machine, and a soil detection unit for detecting soil settlement parameters;

[0042] The operation and analysis module is respectively connected to the shield machine, the precipitation module and the detection module, and is used to integrate the area formed by the average soil pressure and the soil pressure change curve, so as to judge whether the soil is balanced and stable according to the integral value. If the judgment result is unstable, the absolute value of the difference between the actual soil temperature during the construction of the shield machine and the temperature obtained according to the soil temperature gradient is compared with the threshold value. According to the comparison result and whether precipitation occurs, the power of the precipitation well pump is adjusted, the detection period is adjusted, or the construction parameters of the shield machine are optimized.

[0043] Specifically, the fluctuation of soil pressure needs to act for a certain period of time before settlement can occur, so the fluctuation of soil pressure is inversely proportional to the time of settlement. The more violent the fluctuation, the shorter the time required. The embodiment of the present invention thus introduces the integration of the curve and the average value and fixes the monitoring interval, so that the integral value is related to the soil settlement. Through the representation of the integral value, it can be obtained whether there is a possibility of settlement in the future, thereby increasing the timeliness of soil pressure balance monitoring;

[0044] The value of the monitoring interval can be determined according to the actual computing power of the electronic device actually selected for the calculation. The higher the computing power, the smaller the monitoring interval that can be divided. Reasonable selection of the monitoring interval for calculation based on the limited computing power of the electronic device belongs to the existing technology and will not be elaborated here.

[0045] Specifically, the operation and analysis module determines whether the soil is balanced and stable according to the integral value, wherein:

[0046] If the integral value is greater than a preset integral critical value, the soil is determined to be unstable, and the cause of the unstable soil balance is determined based on the temperature deviation value;

[0047] If the integral value is less than the integral critical value, it is determined that the soil balance is stable.

[0048] Specifically, within a single detection cycle, the calculation and analysis module draws a real-time soil pressure curve based on the monitoring data of the soil pressure monitoring unit and obtains the average value of the soil pressure within the detection interval, integrates the areas formed by the starting point and end point of the detection cycle, the soil pressure curve, and the average value of the soil pressure, and sums the obtained integral values ​​to calculate the integral value.

[0049] Specifically, the soil pressure can be adjusted by grouting, drainage or changing the tunneling rate of the shield machine. Any method that can adjust the soil pressure and achieve the effect in the embodiment of the present invention is acceptable and will not be repeated here. The value of the preset integral critical value is obtained by conducting a limited number of soil pressure adjustment experiments on the soil, measuring the soil at the current construction depth without interference from other conditions, and obtaining the minimum value of the integral when settlement occurs.

[0050] See also Figure 2 As shown, it is a flow chart of determining the cause of soil balance instability according to the temperature deviation value according to the present invention.

[0051] If the temperature deviation value is greater than the threshold, it is determined that the cause is the fluctuation of the groundwater level, and measures are taken to increase the pumping power of the dewatering well at the construction site;

[0052] If the temperature deviation value is less than or equal to the threshold, the cause is determined according to the precipitation situation;

[0053] The temperature deviation value is the absolute value of the difference between the standard temperature and the actual temperature.

[0054] Specifically, if the construction site is located in a temperate zone, if the underground depth is ten meters, the surface temperature is thirty degrees Celsius, and the groundwater temperature is 15 degrees Celsius, the thermal conductivity is calculated based on the maximum value of the soil moisture content at the current construction depth to draw the temperature gradient. The temperature obtained at this time is the maximum value of 18 degrees Celsius at the current construction depth, and the minimum temperature should be the groundwater temperature to obtain the standard temperature at the current depth, that is, 15 degrees Celsius. Since the selection of the highest and lowest values ​​is relatively extreme, the standard temperature preferably selects the middle value, which is 16.5 degrees Celsius in the embodiment of the present invention. The threshold is selected as half of the difference between the highest and lowest values. The selection at this time is the most reasonable, that is, 1.5 degrees Celsius.

[0055] Specifically, the operation and analysis module establishes a soil temperature gradient for the current construction area based on the surface temperature and soil thermal conductivity, determines the temperature of the soil under normal conditions at the construction depth based on the temperature gradient and the current construction depth of the shield machine, and records it as the standard temperature.

[0056] See also Figure 3 As shown, it is a flow chart of determining the cause according to the precipitation situation according to the present invention,

[0057] If precipitation occurs and the precipitation is greater than the precipitation threshold, it is determined that the cause of the fluctuation is surface precipitation, and the monitoring period is reduced to a corresponding value according to the precipitation difference;

[0058] If no precipitation occurs or the precipitation is less than or equal to the precipitation threshold, it is determined that there is a problem with the current construction parameters and a construction plan adjustment notice is issued.

[0059] Specifically, precipitation on the surface will affect the groundwater temperature and will continuously bring the surface temperature underground, which will have a certain impact on the underground temperature. At this time, the temperature of the deep soil may be too high or too low. By detecting the precipitation, the influence of surface precipitation on the accuracy of the embodiment of the present invention can be eliminated, thereby ensuring the stability of the automatic detection system for soil pressure balance described in the embodiment of the present invention.

[0060] Specifically, the precipitation threshold is determined by the operation and analysis module according to the soil properties and construction depth of the current construction area. That is, when the precipitation is less than a certain value, the impact on the moisture content of the soil at the current construction depth is less than one percent, and there is basically no effect on the thermal conductivity of the soil, the precipitation value is determined as the precipitation threshold.

[0061] Specifically, the pumping power of the dewatering well at the construction site is adjusted according to the temperature standard deviation to determine the corresponding adjustment coefficient;

[0062] The temperature standard deviation is a difference between the temperature deviation value and the threshold value.

[0063] In detail, the adjustment coefficient is determined according to the power adjustment range of the water pump. The relationship between the temperature standard deviation and the adjustment coefficient can be a functional relationship that satisfies a certain function formula, or it can be a range of power adjustment corresponding to a unit increase in the temperature standard deviation value. As long as there is a positive correlation between the temperature standard deviation and the water pump power, there is no specific limitation on the form of the positive correlation.

[0064] In the embodiment of the present invention, the power adjustment range of the water pump is [60%, 150%] of the rated power. Since the power needs to be increased, that is, the power adjustment range in the embodiment of the present invention is [100%, 150%]. The adjustment method selected in the embodiment of the present invention is:

[0065] Select the preset first-level temperature standard deviation of 0.5 degrees Celsius and the preset second-level temperature standard deviation of 1 degree Celsius;

[0066] comparing the temperature standard deviation with the preset primary temperature standard deviation and the preset secondary temperature standard deviation respectively;

[0067] See also Figure 4 As shown, it is a flow chart for determining the adjustment method selected by the embodiment of the present invention, including:

[0068] If the temperature standard deviation is less than the preset first-level temperature standard deviation, the first adjustment coefficient of 110% is selected to increase the power of the water pump;

[0069] If the temperature standard deviation is greater than or equal to the preset first-level temperature standard deviation and less than or equal to the preset second-level temperature standard deviation, select the second adjustment coefficient of 120% to increase the power of the pump;

[0070] If the temperature standard deviation is greater than the preset first-level temperature standard deviation, a third adjustment coefficient of 130% is selected to increase the power of the water pump;

[0071] Specifically, the monitoring period is adjusted by determining the corresponding period adjustment coefficient according to the precipitation difference;

[0072] The precipitation difference is the difference between the precipitation and the precipitation threshold.

[0073] In detail, the relationship between the precipitation difference and the periodic adjustment coefficient can be a functional relationship that satisfies a certain function formula, or it can be a range of the periodic adjustment coefficient corresponding to a unit increase in the precipitation difference. As long as there is a negative correlation between the precipitation difference and the periodic adjustment coefficient, there is no specific limitation on the form of the negative correlation.

[0074] An embodiment of the present invention provides a method for adjusting a monitoring period, including:

[0075] Select the preset precipitation difference of 5mm. If the precipitation is greater than the preset precipitation difference, the period adjustment coefficient is 0.5; if the precipitation is less than or equal to the preset precipitation, the period adjustment coefficient is 0.8;

[0076] Specifically, after the detection period is adjusted, the preset integral threshold value needs to be adjusted accordingly.

[0077] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. 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 embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An automatic monitoring system for earth pressure balance in shield construction, characterized in that: include: Shield machine; A dewatering module, comprising a water collection well for lowering the groundwater level and a pumping machine arranged in the water collection well for pumping water; The detection module includes an earth pressure monitoring unit for monitoring earth pressure, a temperature detection unit provided in the shield machine for detecting the actual temperature of the soil during the construction of the shield machine, and a soil detection unit for detecting soil settlement parameters; The operation and analysis module is connected to the precipitation module and the detection module respectively, and is used to integrate the area formed by the average soil pressure and the soil pressure change curve, so as to judge whether the soil is balanced and stable according to the integral value. If the judgment result is unstable, the absolute value of the difference between the actual soil temperature during the construction of the shield machine and the temperature obtained according to the soil temperature gradient is compared with the threshold value. According to the comparison result and whether precipitation occurs, the power of the precipitation well pump is adjusted, the detection period is adjusted, or the construction parameters of the shield machine are optimized.

2. The automatic monitoring system for earth pressure balance in shield construction according to claim 1 is characterized in that: The operation and analysis module determines whether the soil is balanced and stable according to the integral value, wherein: If the integral value is greater than a preset integral critical value, it is determined that the soil balance is unstable, and the cause of the soil balance instability is determined according to the temperature deviation value; If the integral value is less than the integral critical value, it is determined that the soil equilibrium is stable.

3. The automatic monitoring system for earth pressure balance in shield construction according to claim 2 is characterized in that: In a single detection cycle, the operation and analysis module draws a real-time earth pressure curve based on the monitoring data of the earth pressure monitoring unit and obtains the average value of the earth pressure in the detection interval, integrates the areas formed by the starting point and end point of the detection cycle, the earth pressure curve, and the average value of the earth pressure, and sums the obtained integral values ​​to calculate the integral value.

4. The automatic monitoring system for earth pressure balance in shield construction according to claim 2 is characterized in that: The cause of soil instability is determined based on the temperature deviation value. If the temperature deviation value is greater than the threshold, it is determined that the cause is the fluctuation of the groundwater level, and measures are taken to increase the pumping power of the dewatering well at the construction site; If the temperature deviation value is less than or equal to the threshold, the cause is determined according to the precipitation situation; The temperature deviation value is the absolute value of the difference between the standard temperature and the actual temperature.

5. The automatic monitoring system for earth pressure balance in shield construction according to claim 4 is characterized in that: The operation and analysis module establishes a soil temperature gradient for the current construction area according to the surface temperature and soil thermal conductivity, and determines the temperature of the soil under normal conditions at the construction depth according to the temperature gradient and the current construction depth of the shield machine and records it as the standard temperature.

6. The automatic monitoring system for earth pressure balance in shield construction according to claim 4, characterized in that: The cause is determined based on the precipitation conditions. If precipitation occurs and the precipitation is greater than the precipitation threshold, it is determined that the cause of the fluctuation is surface precipitation, and the monitoring period is reduced to a corresponding value according to the precipitation difference; If no precipitation occurs or the precipitation is less than or equal to the precipitation threshold, it is determined that there is a problem with the current construction parameters and a construction plan adjustment notice is issued.

7. The automatic monitoring system for earth pressure balance in shield construction according to claim 6 is characterized in that: The precipitation threshold is determined by the operation and analysis module based on the soil properties and construction depth of the current construction area. That is, when the precipitation is less than a certain value, the impact on the moisture content of the soil at the current construction depth is less than one percent, and the precipitation value is determined as the precipitation threshold.

8. The automatic monitoring system for earth pressure balance in shield construction according to claim 4, characterized in that: The pumping power of the dewatering well at the construction site is determined according to the temperature standard deviation; The temperature standard deviation is a difference between the temperature deviation value and the threshold value.

9. The automatic monitoring system for earth pressure balance in shield construction according to claim 6, characterized in that: The adjustment of the monitoring period is determined according to the precipitation difference; The precipitation difference is the difference between the precipitation and the precipitation threshold.

10. The automatic monitoring system for earth pressure balance in shield construction according to claim 9, characterized in that: After the detection period is adjusted, the preset integral threshold value needs to be adjusted accordingly.

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