Tunnel lining internal strain back-pushing grouting pressure control method and system

Abstract

The present application relates to the field of grouting technology, and more particularly to a tunnel lining internal strain backstepping grouting pressure control method and system. The control method comprises: establishing a numerical calculation model, setting the simulated grouting pressure and the grout diffusion range, extracting numerical calculation analysis data, the numerical calculation analysis data including the model tunnel lining inside ring strain value and displacement data; field test injection, the actual grouting pressure is the same as the simulated grouting pressure, obtaining field data, the field data including the field tunnel lining inside ring strain value and displacement data; comparing the numerical calculation analysis data and the field data, modifying the distribution of grouting slurry outside the tunnel lining in the model, adjusting the grout diffusion range, so that the numerical calculation analysis data obtained by model analysis is close to the field data. The method solves the problem that the grout distribution range obtained by the existing acquisition method is poor in fitting with the actual grout distribution.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of grouting technology, in particular to a tunnel lining internal strain backstepping grouting pressure control method and system. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general context of the present application and does not necessarily constitute an acknowledgement or a warranty as to any prior art.

[0003] The grouting process is a construction process commonly used in tunnel maintenance and repair projects to prevent ground subsidence and maintain the stability of the pipe piece. In order to achieve the purpose, the prepared cement slurry is continuously injected into the gap between the tunnel outside and the soil and rock section at a certain grouting pressure, so that the slurry fills the gap and actively reinforces the tunnel pipe piece, providing a safe and stable external environment for underground engineering.

[0004] However, during the grouting process, improper selection and implementation of injection pressure or injection position will increase the risk of tunnel instability, which may lead to many dangerous situations such as ground subsidence, component damage, tunnel floating, etc. Therefore, during the grouting process, the engineering unit needs to prevent the stress of the tunnel outside area distributed by the slurry diffusion from being too large due to excessive grouting pressure, which may eventually cause damage to the tunnel structure. Therefore, during the grouting plan and implementation, accurate pre-calculation and monitoring of the project must be carried out.

[0005] In actual engineering, the main concern of grouting operation is the influence of additional stress generated on the tunnel outside when the slurry diffuses to the gap between the tunnel outside and the soil and rock section. However, under the current technical level, due to the complexity of the geological structure in actual engineering, the soil layer between the grouting point and the tunnel is not uniform, sensors cannot be arranged on the outside of the tunnel, and other factors, the actual diffusion range of the grouting slurry and the actual stress distribution and value of the outside of the tunnel are difficult to obtain directly through field monitoring. Therefore, in order to determine the grouting slurry distribution range and the actual stress distribution and value of the outside of the tunnel in actual engineering, other additional complex technical means are often needed to further obtain the corresponding data.

[0006] According to the inventors' understanding, the current grouting slurry diffusion range and the actual stress distribution and value of the outside of the tunnel are mainly obtained by simply simulating the grouting process through numerical simulation, but due to the complexity of soil composition and the diversity of actual situations of various actual projects, there are often some shortcomings such as complex modeling process, poor fitting of the slurry distribution range on the outside of the tunnel calculated by the model with the actual slurry distribution, poor agreement between the data obtained by numerical calculation and the actual field monitoring data, and inability to effectively use in engineering. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the embodiments of the present application is to provide a tunnel lining internal strain back-propagation grouting pressure control method, which corrects a numerical calculation monitoring model that approximates the real situation and meets the engineering requirements through simulation and mutual feedback, and solves the problems of poor fitting of the slurry distribution range obtained by the existing acquisition method with the actual slurry distribution situation and poor agreement of the acquired data with the actual field monitoring data.

[0008] To achieve the above-mentioned purpose, the embodiments of the present application provide the following technical solutions:

[0009] A tunnel lining internal strain back-propagation grouting pressure control method, comprising: establishing a numerical calculation model, setting a simulated grouting pressure and a slurry diffusion range, extracting numerical calculation analysis data, the numerical calculation analysis data comprising model tunnel lining inside ring strain value and displacement data; field test injection, the actual grouting pressure being the same as the simulated grouting pressure, obtaining field data, the field data comprising field tunnel lining inside ring strain value and displacement data; comparing the numerical calculation analysis data and the field data, modifying the distribution of grouting slurry outside the tunnel lining in the model, adjusting the slurry diffusion range, and making the numerical calculation analysis data obtained by model analysis close to the field data.

[0010] In another preferred embodiment of the present application, the simulated grouting pressure is less than the grouting pressure value in the formal construction plan.

[0011] In another preferred embodiment of the present application, the effectiveness of the numerical calculation model is confirmed after adjusting the slurry diffusion range: a second slurry test injection is performed at the tunnel site, field data is collected, the analysis data obtained by the improved numerical calculation model is verified and compared with the field data, and the effectiveness of the model is confirmed.

[0012] In another preferred embodiment of the present application, if the numerical calculation analysis data of the second test injection is consistent with the field data, formal grouting is performed; if not, the model is modified, the test injection process is repeated and compared and verified, until the numerical calculation analysis data of the test injection is consistent with the field data.

[0013] In another preferred embodiment of the present application, after confirming the effectiveness of the model, the grouting pressure at the time of formal grouting is set, the tunnel lining exterior data of the numerical calculation model is obtained, and it is judged whether it exceeds the tunnel stress safety threshold.

[0014] In another preferred embodiment of the present application, if it does not exceed, the safety control value of the grouting pressure is determined; if it exceeds, the grouting scheme is modified so that it does not exceed the tunnel stress safety threshold, and then the safety control value of the grouting pressure is determined.

[0015] In another preferred embodiment of the present application, the external data comprises an equivalent stress outside the tunnel lining.

[0016] The tunnel lining internal strain backstepping grouting pressure control system also provided by the embodiment of the present application comprises a monitoring unit and a numerical calculation analysis unit; a numerical calculation model is established by the numerical calculation analysis unit, the simulated grouting pressure and the slurry diffusion range are set, and numerical analysis data are extracted, wherein the numerical analysis data comprise a model tunnel lining inside circumferential strain value and displacement data; the monitoring unit acquires field data of a trial injection, and the field data comprise field tunnel lining inside circumferential strain value and displacement data; the analysis data and the field data are compared, the distribution of grouting slurry outside the tunnel lining in the numerical model is modified, the slurry diffusion range is adjusted, and the data obtained by the numerical model analysis is close to the field data.

[0017] In another preferred embodiment of the present application, the monitoring unit comprises a vibrating string sensor dynamic acquisition instrument, a sensor and safety monitoring system software; the sensor is arranged inside the tunnel lining; the vibrating string sensor dynamic acquisition instrument acquires strain changes of a structure to be measured by measuring data of the sensor; and the safety monitoring system software is used for real-time monitoring of the collected data; and the numerical analysis software comprises, but is not limited to, Abaqus, Ansys, PFC, EDEM and the like.

[0018] In another preferred embodiment of the present application, the sensor is a steel string sensor; and the vibrating string sensor dynamic acquisition instrument acquires strain changes of a structure to be measured by measuring frequency changes of the steel string arranged in the sensor.

[0019] The one or more technical solutions provided in the embodiment of the present application have at least the following technical effects or advantages:

[0020] 1. The control method of the present application is fed back by calculation and monitoring, and finally a monitoring model close to the real situation and sufficient to meet the engineering requirements is obtained, thereby solving the problems that the slurry distribution range obtained by the existing acquisition method is poorly fitted with the actual slurry distribution situation, and the acquired data is poorly consistent with the actual field monitoring data.

[0021] 2. The existing method of obtaining the distribution range of slurry outside a tunnel by forward deduction of grouting operation has a very high requirement for model precision, the present application obtains the distribution range of slurry outside a tunnel by backstepping method, reduces the requirement for the model, and obtains strain and displacement results consistent with actual field construction monitoring values.

[0022] 3. The control method of the present application can simulate the grouting scheme in actual construction on the basis of obtaining the slurry distribution range, provide prediction data of the planned grouting scheme, and provide effective prediction and safety evaluation for actual construction. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, and are incorporated into and constitute a part of this specification. The embodiments of the application, and their

[0024] Figure 1 It is a tunnel lining internal strain backstepping grouting pressure control method schematic diagram of the embodiment of the application;

[0025] Figure 2 It is a grouting point position schematic diagram of the embodiment of the application;

[0026] In the figure: 1, grouting equipment; 2, grouting pipeline; 3, grouting port; 4, tunnel structure; DETAILED DESCRIPTION

[0027] It should be noted that the following detailed description is exemplary and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0028] It should be noted that the terms used herein are only intended to describe specific embodiments, and are not intended to limit the exemplary embodiments according to the application. As used herein, unless otherwise explicitly stated in the application, the singular form is also intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or combination thereof.

[0029] As introduced in the background, at present, the grouting slurry diffusion range and the actual stress distribution outside the tunnel are mainly obtained by simply simulating the grouting process by numerical calculation, but due to the complexity of soil composition and the difference of actual situation of each actual project, there are often some shortcomings such as complex modeling process, poor fitting of slurry distribution range outside the tunnel calculated by numerical model, poor agreement between data obtained by numerical calculation and actual field monitoring data, and inability to effectively use in engineering. In order to solve the above technical problems, the present application provides a tunnel lining internal strain backstepping grouting pressure control method.

[0030] The control method uses a device for monitoring the internal strain of the tunnel lining, which includes a vibrating string sensor dynamic acquisition instrument, a sensor, a safety monitoring system software, and a numerical simulation analysis software.

[0031] The sensor is arranged inside the tunnel lining, the sensor has a steel string inside, the vibrating string sensor dynamic acquisition instrument obtains the strain change of the structure to be measured by measuring the frequency change of the steel string arranged in the sensor, the safety monitoring system software is used for real-time monitoring of the collected data, the numerical calculation software obtains analysis data by establishing a numerical calculation model to simulate the actual working condition on site. The vibrating string sensor dynamic acquisition instrument and the sensor are suitable for long-term strain monitoring of steel structures or concrete structures, including surface strain measurement of concrete structures or steel structures such as bridges, tunnels, foundation pit supports, columns and steel sheet piles.

[0032] A tunnel lining internal strain back-propagation grouting pressure control method (as shown in Figure 1 The method comprises the following steps:

[0033] 1. A numerical calculation software is used to establish an overall numerical calculation model of the soil layer, the tunnel lining section and the grouting point according to the actual engineering drawings, and the grouting of the tunnel under the set grouting pressure and the grouting point is simulated.

[0034] A tunnel model is established using a numerical simulation calculation method, the grouting pressure value is set as the planned grouting pressure of the first slurry test grouting, and the test grouting pressure value is less than the planned grouting pressure value of the formal construction. According to the positional relationship between the grouting point and the tunnel, the distribution of the slurry outside the tunnel lining is preliminarily empirically estimated, and the slurry diffusion range is set.

[0035] The pressure parameter outside the lining is set, the model is subjected to numerical calculation pre-simulation analysis, and the ring strain value, horizontal displacement and longitudinal displacement data of the model tunnel lining inside are extracted.

[0036] 2. Data collection is carried out on site: vibrating string sensor dynamic acquisition instruments and sensors are arranged at appropriate points inside the tunnel lining according to the actual situation on site, the first slurry test grouting is carried out (the grouting points in each quadrant are as shown in Figure 2 The corresponding ring strain value, horizontal displacement and longitudinal displacement data of the site tunnel lining inside at the corresponding points under the corresponding grouting pressure are obtained through the sensor.

[0037] 3. The numerical calculation analysis data and the site data are compared, the distribution of the grouting slurry outside the tunnel lining in the numerical calculation model is modified, the slurry diffusion range is adjusted, the internal ring strain value obtained by the numerical calculation software analysis is close to the actual monitoring data, and the distribution of the grouting slurry outside the tunnel lining in the numerical calculation model is further approximated to the real slurry distribution by back-propagation.

[0038] 4. Perform a second trial injection (in-situ trial injection, only change the trial injection grouting pressure setting), verify and compare the obtained hoop strain, horizontal displacement and longitudinal displacement data of the improved model with the corresponding point hoop strain value, horizontal displacement and longitudinal displacement data of the tunnel lining in the field, and confirm the effectiveness of the model. If the numerical calculation and analysis data of the second trial injection are consistent with the field data, formal grouting is performed; if not, modify the numerical calculation model, repeat the trial injection process and compare and verify, until the numerical calculation and analysis data of the trial injection are consistent with the field data.

[0039] 5. Obtain the numerical values of the numerical calculation model tunnel lining outside, including the obtained hoop strain, horizontal displacement and longitudinal displacement data, compare the tunnel stress safety threshold, and confirm whether the safety of the tunnel under the formal grouting pressure is reliable. Determine the safety control value of the grouting pressure.

[0040] Set the grouting pressure during formal grouting, obtain the equivalent stress of the model tunnel lining outside, and determine whether it exceeds the tunnel stress safety threshold. If not, determine the safety control value of the grouting pressure; if so, modify the grouting scheme so that it does not exceed the tunnel stress safety threshold, and then determine the safety control value of the grouting pressure.

[0041] Through the above method, the application has the following technical effects:

[0042] Firstly, the control method is fed back through calculation and monitoring, and finally a monitoring model close to the actual situation and sufficient to meet the engineering requirements is obtained.

[0043] Secondly, the distribution range of the tunnel outside the diffused grout is obtained by the back-propagation method, which avoids the problem of requiring high precision of the model when using the method of obtaining the distribution range of the tunnel outside the diffused grout from the forward deduction of the grouting operation, and the obtained strain and displacement results are consistent with the actual monitoring values in the field.

[0044] Furthermore, the control method can simulate the grouting scheme during actual construction based on the obtained grout distribution range, provide prediction data for the planned grouting scheme, and provide effective prediction and safety evaluation for actual construction.

[0045] In addition, sensors cannot be placed on the outside of the tunnel lining (between the soil and the outside of the tunnel lining), so the most important grout distribution and pressure on the outside of the tunnel lining cannot be monitored. This method simulates the grout distribution range and grouting pressure on the outside of the tunnel lining by measuring the strain and displacement data inside the tunnel lining through numerical calculation.

[0046] (1) The control method can be used in scenarios where the grouting pressure cannot be actually monitored in engineering, and the grouting pressure in engineering is simulated and obtained through the control method;

[0047] (2) The control method can be used to obtain the diffusion range of the final slurry outside the tunnel segment during grouting operation;

[0048] (3) The control method can be used to determine the safety threshold of the strain displacement values of the tunnel during grouting construction;

[0049] (4) The control method simulates the strain and displacement data of the tunnel under the planned grouting pressure through a numerical calculation model, and when the monitoring system monitoring data reaches the model predicted value after actual grouting, the grouting can be stopped. Therefore, it can be used to assist in determining the maximum time of the grouting process;

[0050] (5) The control method can be used to simulate the actual construction grouting scheme in advance, provide prediction data corresponding to the grouting scheme, and provide effective prediction and safety evaluation for actual construction.

[0051] (6) During field monitoring, the prediction data obtained in advance by the control method can be used to compare with the real-time monitoring data obtained during grouting, and has a certain early warning effect on the situation that improper grouting leads to the destruction of the tunnel structure.

[0052] Although the specific embodiments of the present application have been described above with reference to the drawings, it is not a limitation on the scope of protection of the present application, and those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present application without creative labor are still within the scope of protection of the present application.

Claims

1. A method for controlling the grouting pressure by reverse strain estimation inside tunnel lining, characterized in that, include: A numerical calculation model is established, the simulated grouting pressure and grout diffusion range are set, and numerical calculation analysis data is extracted. The numerical calculation analysis data includes the circumferential strain value and displacement data of the inner side of the tunnel lining in the model. On-site grouting was performed, and the actual grouting pressure was the same as the simulated grouting pressure. On-site data was obtained, including the circumferential strain value and displacement data of the inner side of the tunnel lining. By comparing the numerical calculation analysis data with the field data, the distribution of grout outside the tunnel lining in the numerical calculation model is modified, and the grout diffusion range is adjusted so that the numerical calculation analysis data obtained from the numerical calculation model is closer to the field data; the reverse calculation method makes the distribution of grout outside the tunnel lining in the numerical calculation model further approximate the actual grout distribution. After adjusting the grout diffusion range, the effectiveness of the numerical calculation model was confirmed: a second grout test injection was conducted at the tunnel site, and field data was collected. The numerical calculation analysis data obtained by the improved numerical calculation model was compared with the field data for verification. If the numerical calculation analysis data of the second test injection matched the field data, formal grouting was carried out; if they did not match, the numerical calculation model was modified, the test injection process was repeated, and the comparison and verification were carried out until the numerical calculation analysis data of the test injection matched the field data, thus confirming the effectiveness of the model. After confirming the model's validity, the grouting pressure for formal grouting is set, and external data of the tunnel lining in the numerical calculation model are obtained to determine whether the stress exceeds the tunnel's safety threshold.

2. The method for controlling the internal strain of tunnel lining by reverse grouting pressure as described in claim 1, characterized in that, The simulated grouting pressure is lower than the planned grouting pressure during the actual construction.

3. The method for controlling the internal strain of tunnel lining by reverse grouting pressure as described in claim 1, characterized in that, If the pressure is not exceeded, then determine the safe control value for the grouting pressure; If the stress exceeds the limit, the grouting plan should be modified to ensure it does not exceed the tunnel stress safety threshold, and then the safe control value for the grouting pressure should be determined.

4. The method for controlling the internal strain of tunnel lining by reverse grouting pressure as described in claim 1, characterized in that, External data include external von mises equivalent stresses of the tunnel lining.

5. A strain-back grouting pressure control system for tunnel lining, characterized in that, It includes a monitoring unit and a numerical calculation and analysis unit; A numerical calculation model is established using the numerical calculation and analysis unit. The simulated grouting pressure and grout diffusion range are set, and numerical calculation and analysis data are extracted. The numerical calculation and analysis data includes the circumferential strain value and displacement data of the inner side of the tunnel lining in the model. The monitoring unit acquires field data from the test injection, including the circumferential strain value and displacement data of the inner side of the tunnel lining. By comparing the numerical calculation analysis data with the field data, the distribution of grout outside the tunnel lining in the numerical calculation model is modified, and the grout diffusion range is adjusted so that the numerical calculation analysis data obtained from the numerical calculation model is closer to the field data; the reverse calculation method makes the distribution of grout outside the tunnel lining in the numerical calculation model further approximate the actual grout distribution. After adjusting the grout diffusion range, the effectiveness of the numerical calculation model was confirmed: a second grout test injection was conducted at the tunnel site, and field data was collected. The numerical calculation analysis data obtained by the improved numerical calculation model was compared with the field data for verification. If the numerical calculation analysis data of the second test injection matched the field data, formal grouting was carried out; if they did not match, the numerical calculation model was modified, the test injection process was repeated, and the comparison and verification were carried out until the numerical calculation analysis data of the test injection matched the field data, thus confirming the effectiveness of the model. After confirming the model's validity, the grouting pressure for formal grouting is set, and external data of the tunnel lining in the numerical calculation model are obtained to determine whether the stress exceeds the tunnel's safety threshold.

6. The tunnel lining internal strain reverse grouting pressure control system as described in claim 5, characterized in that, The monitoring unit includes a vibrating wire sensor dynamic acquisition instrument, a sensor, and safety monitoring system software. The sensor is arranged inside the tunnel lining. The vibrating wire sensor dynamic acquisition instrument obtains the strain changes of the structure under test by measuring the data of the sensor. The safety monitoring system software is used to monitor the acquired data in real time. The numerical calculation and analysis unit includes Abaqus, Ansys, PFC, and EDEM numerical calculation software.

7. The tunnel lining internal strain reverse grouting pressure control system as described in claim 6, characterized in that, The sensor is a steel wire sensor, and the vibrating wire sensor dynamic acquisition instrument obtains the strain change of the structure under test by measuring the frequency change of the steel wire set inside the sensor.

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