Expansion mud sandstone diversion tunnel steel frame difference reserved deformation construction method

Abstract

The invention relates to the technical field of tunnel construction, in particular to an expansive mud sandstone diversion tunnel steel frame difference reserved deformation construction method which comprises the steps that S1, tunnel excavation is conducted, specifically, excavation is conducted at the specified depth in a specified area; s2, accurate measurement: scanning each step by using a three-dimensional laser scanner to obtain a large amount of point cloud data, and fitting the section condition of the steel frame in each construction stage to obtain the section deformation condition; s3, analyzing the deformation amount of the steel frame, wherein the deformation amount of the steel frame is a value obtained by subtracting the accumulated deformation amount from the reserved amount of the unified prefabricated steel frame; s4, prefabricating the differentiated steel frame in a factory: performing reserved deformation treatment on each steel frame arch foot according to the calculated total reserved deformation of the steel frame, determining the reserved deformation of each section of steel frame, and drawing a steel frame processing drawing; s5, transportation, installation and supporting are conducted, specifically, the prefabricated steel frame is transported to a tunnel site, and installation and primary supporting are conducted; the method has the effect of flexibly adjusting the reserved deformation according to different geological conditions.

Description

Technical Field

[0001] The present application relates to the technical field of tunnel construction, and in particular to a construction method for differential reserved deformation of a steel frame of an expansive mud-sandstone water diversion tunnel. Background Art

[0002] As a special geological material, expansive mudstone is widely used in water conservancy project construction, especially in the construction of water diversion tunnels. Due to its characteristic of swelling when exposed to water, it poses a great challenge to the stability of the tunnel arch. Traditional construction methods usually rely on experience and technical specifications. Although they can guarantee construction quality and safety to a certain extent, they still have certain limitations when facing complex geological conditions. With the advancement of science and technology and the development of construction technology, people have begun to explore more scientific and precise methods to deal with the construction difficulties of expansive mudstone water diversion tunnels in order to improve the stability of tunnel structures and construction efficiency.

[0003] Among the existing technical means, in order to deal with the problem of arch deformation caused by expansive mud-sandstone, some conventional measures are usually taken. For example, a general reserved deformation amount is determined through simple geological surveys before construction, and this standard is uniformly applied throughout the tunnel construction process. In addition, high-strength materials may be used to enhance the stiffness of the arch, or temporary supports may be added during the construction process to reduce the impact of expansive mud-sandstone on the arch. Although these methods can alleviate the deformation problem to a certain extent, there are still many shortcomings.

[0004] With regard to the above-mentioned related technologies, the main defects of the above-mentioned conventional means are the lack of flexibility and pertinence. Due to the diversity and complexity of geological conditions, a unified standard for reserved deformation is difficult to adapt to the specific conditions of different locations, resulting in insufficient arch deformation in some areas and excessive reservation in other areas, thereby causing waste of resources and potential safety hazards. Therefore, there is an urgent need for a construction method that can flexibly adjust the reserved deformation according to different geological conditions to effectively improve the construction accuracy and safety. Summary of the invention

[0005] In order to solve the problem of reasonably determining and implementing differentiated reserved deformation according to different geological conditions, the present application provides a construction method for differentiated reserved deformation of a steel frame of an expansive mud-sandstone water diversion tunnel.

[0006] The present application provides a construction method for differential reserved deformation of a steel frame of an expansive mud-sandstone water diversion tunnel, which adopts the following technical solution: A construction method for differential reserved deformation of a steel frame of an expansive mud-sandstone water diversion tunnel, comprising: S1: Tunnel excavation: Select a suitable area before excavation and excavate the specified depth in the specified area; S2: Precise measurement: The total station is set up using the rear intersection free station setting method, and a 3D laser scanner is used to scan each step to obtain a large amount of point cloud data, and the cross-section of each steel frame is obtained. The cross-section of the steel frame at each construction stage is fitted to obtain the cross-section deformation and the deformation of the steel frame; S3: Analyze the deformation of the steel frame: The deformation of the steel frame is the value obtained by subtracting the accumulated deformation from the reserved amount of the uniform prefabricated steel frame; S4: Factory prefabricated differentiated steel frame: According to the calculated total reserved deformation of the steel frame, the reserved deformation of each steel frame arch foot is processed, the reserved deformation of each section of the steel frame is determined, and the steel frame processing drawings are drawn to process the steel frame; S5: Transportation, installation and support: transport the prefabricated steel frame to the tunnel site and carry out installation and initial support.

[0007] By adopting the above technical solution, a specified depth is excavated in a suitable area. Then, according to the construction requirements, the total station and the 3D laser scanner are set up at the specified position. Through the measurement of the 3D laser scanner, detailed point cloud data can be obtained, and then the deformation of the steel frame is obtained and the deformation of the steel frame is analyzed. After that, the obtained data will be drawn into a processing drawing, and the factory will process the steel frame. After the processing is completed, the steel frame will be transported to the tunnel, installed in a suitable position, and supported. This application obtains detailed point cloud data through the joint use of the total station and the 3D laser scanner to ensure the cross-sectional situation of each steel frame. The accurate measurement of the steel frame condition and deformation provides reliable data support for subsequent analysis. By fitting the steel frame cross-section conditions at each construction stage and providing real-time feedback on the deformation of the steel frame, the reserved deformation of each steel frame can be dynamically adjusted according to the actual geological conditions and construction progress, which enhances the flexibility and adaptability of the construction. Since the reserved deformation of each steel frame is customized according to actual needs, it avoids the waste of resources caused by the unified reserved deformation in the traditional method, saving materials and costs. Through precise measurement and dynamic adjustment, rework and adjustment caused by improper deformation are reduced, the construction progress is accelerated, and the construction efficiency is improved. The reserved deformation of each steel frame is accurately calculated to ensure the stability and safety of the steel frame during the construction process, and reduce the safety hazards caused by insufficient or excessive reserved deformation. Through the feedback of the deformation of the steel frame in the initial support, a closed-loop system with continuous optimization is formed, which ensures the rationality of the support design, further improves the construction quality, realizes the construction of differential reserved deformation of the steel frame of the expansive mud sandstone water diversion tunnel, and significantly improves the construction accuracy and safety.

[0008] In a specific implementation scheme, step S2 includes S21: Preparation before measurement: burying control points and setting up prism balls; S22: Scanning and data processing: The total station is set up using the resection free stationing method. The unique coordinates of the two spherical prisms are measured by the total station. A 3D laser scanner is used to scan each step to obtain a large amount of point cloud data. The cross-section of the steel frame at each construction stage is fitted to obtain the cross-section deformation. S23: Feedback on deformation: The reserved deformation of the steel frame of the upper step is determined according to the local geological conditions, and the remaining steel frames are determined by the cumulative deformation of the steel frames of the same section on the upper step.

[0009] By adopting the above technical scheme, the deformation of the steel frame of the expansive mud sandstone water diversion tunnel can be accurately measured and flexibly adjusted. Specifically: the accuracy and reliability of the measurement are ensured. By accurately burying control points and setting up prism balls at the predetermined positions of the tunnel, the surrounding rock deformation and steel frame displacement during the tunnel construction process can be monitored in real time, providing accurate basic data for subsequent data processing; the tunnel steps are scanned using a total station and a three-dimensional laser scanner to obtain a large amount of point cloud data, which is processed through data analysis software to obtain the cross-sectional conditions and deformation of each steel frame. This method not only improves the accuracy of the measurement, but also provides real-time feedback on the deformation during the construction process, providing a basis for subsequent construction adjustments; by accurately calculating the reserved deformation of the upper step steel frame, and dynamically adjusting the reserved deformation of other steel frames based on the cumulative deformation of the previous step, the deformation of the steel frame under different geological conditions can be accurately controlled, and the reserved deformation can be flexibly adjusted according to different geological conditions; this can avoid the waste of resources and safety hazards caused by the unified reserved deformation in the traditional method, and improve the accuracy and safety of construction.

[0010] In a specific feasible implementation scheme, in step S3, the deformation of the steel frame is greater than zero for convergence, the deformation of the steel frame is less than zero for expansion, and the deformation of the steel frame is equal to zero for the same prefabrication deformation in the factory.

[0011] By adopting the above technical scheme, the deformation state of each steel frame can be accurately judged according to the actual measured deformation of the steel frame; when the deformation of the steel frame is greater than zero, it indicates that the steel frame has converged, indicating that the reserved deformation is sufficient and can effectively cope with the pressure of the surrounding rock; when the deformation of the steel frame is less than zero, it indicates that the steel frame has expanded, suggesting that the reserved deformation needs to be increased to prevent the steel frame from being damaged due to excessive pressure; when the deformation of the steel frame is equal to zero, it indicates that the current reserved deformation is consistent with the actual demand and no adjustment is required. This method can dynamically adjust the reserved deformation to ensure that the steel frame always maintains the best stress state during the construction process, thereby improving the safety and economy of tunnel construction.

[0012] In a specific feasible implementation scheme, in step S4, the steel frame is prefabricated. Since the deformation of each steel frame is different and the deformation amount is small and cannot be distinguished by the naked eye, a QR code needs to be attached to the bottom of the steel frame after it is manufactured.

[0013] By adopting the above technical solution, it is possible to ensure that the deformation of each steel frame is effectively managed and identified during the prefabrication process. Since the deformation of each steel frame is different and small, it is impossible to distinguish them with the naked eye. Therefore, a QR code is affixed to the bottom of the steel frame after it is manufactured. The specific position and deformation information of each steel frame can be easily tracked and managed. This not only improves the accuracy of steel frame installation, but also ensures efficiency and safety during the construction process, and reduces the risks and rework costs caused by incorrect installation.

[0014] In a specific feasible implementation scheme, in step S5, during the process of transporting the prefabricated steel frame to the tunnel site, a special fixing device may be installed on the transport vehicle to ensure that the steel frame does not move or overturn during transportation.

[0015] By adopting the above technical solution, it is ensured that the prefabricated steel frame will not move or overturn during transportation, effectively preventing damage or deformation of the steel frame caused by improper transportation, ensuring the integrity of the steel frame, and improving the safety and construction quality of the construction site.

[0016] In a specific feasible implementation scheme, in step S2, composite measurement is performed in combination with geological radar, and the point cloud data and geological radar data are imported into the three-dimensional laser scanner data analysis software to generate a scanning cloud map of the section where the steel frame is located.

[0017] By adopting the above technical solution, combined with geological radar for composite measurement, importing point cloud data and geological radar data into the 3D laser scanner data analysis software, and generating a scanning cloud map of the section where the steel frame is located, we can have a more comprehensive understanding of the geological conditions of the tunnel and improve the accuracy and reliability of the measurement. The underground rock layer distribution information provided by the geological radar combined with the point cloud data obtained by the 3D laser scanner can help to more accurately calculate the cumulative deformation of each steel frame in different construction progress, so as to better guide the construction process and ensure that the deformation of the steel frame is always within a controllable range.

[0018] In a specific implementation scheme, step S5 includes S51: After arriving at the site, the steel frame needs to be inspected again. Before the steel frame enters the hole, the workers should scan the QR code to determine the specific location of the steel frame, and confirm it again before installation.

[0019] By adopting the above technical solution, the accuracy and safety of the prefabricated steel frame during transportation and installation are ensured; by conducting a secondary inspection of the steel frame and scanning the QR code to confirm the specific position of the steel frame before installation, construction errors caused by steel frame mismatch can be avoided, and construction accuracy and efficiency can be improved. At the same time, the safety hazards caused by steel frame mismatch are reduced, ensuring the safety of on-site workers.

[0020] In a specific implementation scheme, step S5 further includes S52: Steel frame installation: When installing the steel frame, first use a pickaxe to carefully chisel away the concrete at the arch foot to expose the connecting steel plate and clean up the debris at the bolt holes. The two sections of the steel frame are fastened together by connecting the steel plate and bolts. The connecting steel plate should be tightly attached and the steel frame should be installed perpendicular to the centerline of the tunnel.

[0021] By adopting the above technical scheme, firstly, a pickaxe is used manually to expose the connecting steel plate and clean up the debris at the bolt hole, thereby ensuring the cleanliness and flatness of the connecting part, reducing the error in the installation process, and ensuring the accuracy and stability of the steel frame installation; secondly, the two sections of the steel frame are fastened together by connecting the steel plate and bolts, and the connecting plate should be tightly fitted, which enhances the connection strength between the steel frames and prevents loosening and deformation of the connecting parts; finally, the steel frame should be installed in place perpendicular to the center line of the tunnel, ensuring the overall structural stability and uniform force of the steel frame, and improving the construction quality and safety of the tunnel.

[0022] In a specific feasible implementation scheme, in step S52, when the foundation strength at the arch foot is insufficient or the arch foot elevation is inaccurate, a concrete pad should be set for adjustment, the steel frame should be in close contact with the wall surface, and the gap with the surrounding rock should be wedged and filled tightly with shotcrete.

[0023] By adopting the above technical scheme, when the foundation strength at the arch foot is insufficient or the arch foot elevation is inaccurate, concrete pads are set for adjustment to ensure the stability and accuracy of the steel frame and avoid deformation and instability of the steel frame caused by foundation problems; the steel frame should be in close contact with the wall, and the gap with the surrounding rock should be wedged and filled tightly with shotcrete, which can increase the friction between the steel frame and the surrounding rock, enhance the support effect, and prevent the surrounding rock from becoming unstable due to gaps between the steel frame and the surrounding rock, thereby ensuring the safety and stability of the tunnel structure.

[0024] In a specific implementation scheme, step S5 further includes S53: The deformation of the steel frame in the initial support is fed back to the precise calculation, and then the steel frame of the upper step is prefabricated according to the total reserved deformation obtained by calculation so that its deformation reaches the shape of the designed section, forming a cycle.

[0025] By adopting the above technical scheme, the actual deformation of the steel frame in the initial support can be fed back to the precise calculation system, and the reserved deformation of each section of the steel frame can be recalculated, thereby realizing dynamic adjustment of the reserved deformation of the steel frame; it can not only better adapt to complex and changeable geological conditions, but also ensure that the deformation of the steel frame is always within a controllable range, thereby improving the stability and safety of the tunnel structure, while promoting construction progress and saving costs.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: The designed construction method of differential reserved deformation of steel frame for expansive mud-sandstone water diversion tunnel obtains detailed point cloud data through the joint use of total station and 3D laser scanner, ensuring the accurate measurement of cross-section and deformation of each steel frame, providing reliable data support for subsequent analysis, and fitting the cross-section of the steel frame at each construction stage and real-time feedback of the deformation of the steel frame, so that the reserved deformation of each steel frame can be dynamically adjusted according to the actual geological conditions and construction progress, enhancing the flexibility and adaptability of construction, reducing rework and adjustment caused by improper deformation through precise measurement and dynamic adjustment, accelerating the construction progress, improving construction efficiency, realizing differential reserved deformation construction of steel frame for expansive mud-sandstone water diversion tunnel, and significantly improving construction accuracy and safety.

[0027] The designed construction method of differential reserved deformation of steel frames for expansive mud-sandstone water diversion tunnel can achieve precise control of steel frame deformation under different geological conditions and flexibly adjust reserved deformation according to different geological conditions by accurately calculating the reserved deformation of the upper step steel frame and dynamically adjusting the reserved deformation of other steel frames based on the accumulated deformation of the previous step. This can avoid the waste of resources and safety hazards caused by the unified reserved deformation in traditional methods and improve the accuracy and safety of construction.

[0028] The designed construction method of differential reserved deformation of the steel frame of the expansive mud-sandstone water diversion tunnel is combined with geological radar for composite measurement. The point cloud data and geological radar data are imported into the 3D laser scanner data analysis software to generate a scanning cloud map of the section where the steel frame is located, which can provide a more comprehensive understanding of the geological conditions of the tunnel and improve the accuracy and reliability of the measurement. The underground rock layer distribution information provided by the geological radar is combined with the point cloud data obtained by the 3D laser scanner to help more accurately calculate the cumulative deformation of each steel frame in different construction progress, thereby better guiding the construction process and ensuring that the deformation of the steel frame is always within a controllable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a process flow chart of an embodiment of the present application.

[0030] Figure 2It is a schematic diagram of the installation structure of the upper step steel frame and the middle step steel frame in the embodiment of the present application.

[0031] Figure 3 It is a schematic diagram of the installation structure of the upper step steel frame, the middle step steel frame and the lower step steel frame in the embodiment of the present application.

[0032] Explanation of the accompanying drawings: 1. upper step; 2. middle step; 3. lower step; 4. steel frame. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-3 This application is described in further detail.

[0034] The embodiment of the present application discloses a construction method for differential reserved deformation of a steel frame of an expansive mud-sandstone water diversion tunnel. Example 1

[0035] Reference Figure 1 , Figure 2 and Figure 3 A construction method for differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel includes: S1: Tunnel excavation: Select a suitable area before excavation, and excavate the designated depth in the designated area. To reduce the disturbance of the surrounding rock, step excavation is adopted for tunnel construction. The spacing of the surrounding rock tunnel monitoring section is 5-10m. The measuring points of the shallow buried section of the tunnel entrance should be densely arranged, and the arch settlement and peripheral convergence measuring points should be arranged on the same section; S2: Precise Measurement S21: Preparation before measurement S211: Burying of control points: Before construction, control points need to be accurately buried at the predetermined locations of the tunnel; these control points usually include measurement benchmarks and deformation monitoring points, which are used to monitor the deformation of the surrounding rock and the displacement of the steel frame 4 during the tunnel construction process. The control points need to be buried in a location with hard soil for long-term storage and convenient use; S212: Setting up the prism ball: When the two spherical prisms are placed, the distance between each other and the distance from the 3D laser scanner should be greater than 3m and less than 5m (the 3D laser scanner and the total station are roughly equilateral triangles); the height difference between the two spherical prisms must be greater than 3cm; when the two spherical prisms are placed, the prisms face the total station, and the white arc surface on the back of the prism faces the 3D laser scanner. The total station and the 3D laser scanner can be set up on both sides of the tunnel centerline respectively; if multi-station scanning is required, the total station can be set up in the middle of the section to be scanned; when the total station measures the spherical prism, the prism mode must be set to Leica circular prism mode (prism constant is -34.4mm), and the prism height is set to 0; use a strong flashlight to illuminate the spherical prism and accurately measure the prism center value, accurately record the measured coordinates and elevations of the two spherical prisms, and check whether they are the measurement results of the circular prism height of 0; S22: Scanning and data processing S221: The total station is set up using the rear intersection free station method. The unique coordinates of the two spherical prisms are measured by the total station, and a series of point cloud data can be obtained by automatic cross-section scanning. The point cloud data and the measured spherical prism positions are imported into the "PCAS" software that comes with the 3D laser scanner. The cloud data is processed using the software that comes with the instrument to obtain an original data map.

[0036] In the step method construction, the excavation and support of each step section is a process of unloading and loading the surrounding rock; in the tunnel excavation process, first use a 3D laser scanner to scan each step to obtain a large amount of point cloud data. During the scanning process, ensure that the scanning covers every corner of the entire tunnel (the scanner can be handheld or fixed on a bracket. The specific choice depends on the actual situation on site. The choice of scanner can be adjusted according to the accuracy requirements. For example, a scanner with millimeter accuracy can be selected to ensure the accuracy of the data); S222: After inputting the support type and surrounding rock type and setting all the above data, cut off at each steel frame 4 and generate a data report, so that the cross-section of each steel frame 4 can be obtained. The cross-section deformation of the steel frame 4 in each construction stage can be obtained by fitting the cross-section of the steel frame 4; S23: Feedback deformation: The strength of the weak surrounding rock is low, and the self-stabilization ability is poor once excavated. Therefore, each step can be controlled within 3 to 5 meters. The cross-section after excavation should be closed as soon as possible to shorten the initial support ring time. This can minimize the spatial deformation caused by time, which is more conducive to deformation control and timely reflection of deformation. The deformation of each angle of the steel frame 4 of the upper and middle steps 2 can be clearly obtained through the cross-sectional diagram of the steel frame 4 of the upper and middle steps 2. The total reserved deformation of the arch of the middle step 2 is the total reserved deformation calculated based on the measured cumulative deformation of the upper step 1. The reserved deformation is determined by the reserved deformation of the arch of the lower step 3, and the total reserved deformation is determined by the accumulated deformation of the arch foot of the middle step 2; except that the reserved deformation of the steel frame 4 of the upper step 1 is determined according to the local geological conditions, the remaining steel frames 4 are determined by the accumulated deformation of the steel frames 4 of the same section of the upper step. Therefore, each section of the steel frame 4 is different, which can better fit the site environment, thereby achieving smooth connection, ensuring the integrity and internal safety of the steel frame 4, improving the ability of the steel frame 4 to resist surrounding rock deformation, ensuring the safety of on-site workers, promoting construction progress, and saving costs; S3: Analysis of the deformation of the steel frame 4: The deformation of the steel frame 4 is the value obtained by subtracting the accumulated deformation from the reserved amount of the unified prefabricated steel frame 4; as shown in Table 1 below, since the deformation of the two steel frames 4 on each step is different, they are analyzed separately; the calculation method of the total deformation of the middle step 2 is similar to that of the upper step 1. The total reserved deformation of the arch of the middle step 2 is S1, and the total reserved deformation of the arch of the lower step 3 is S2, and the calculation method is as shown in Table 1 Table 1 Calculation method of total reserved deformation

[0037] l 1左 : The reserved deformation amount of the arch foot of the left side steel frame 4 of the upper step 1 is preset according to the geological conditions on site during design.

[0038] l 1右 : The arch foot of the steel frame 4 on the right side of the upper step 1 is designed with a preset reserved deformation amount based on the geological conditions on site.

[0039] l 2左 : The reserved deformation amount of the steel frame 4 arch foot on the left side of the middle step 2 is preset according to the geological conditions on site during design.

[0040] l 2右 : The reserved deformation amount of the steel frame 4 arch foot on the right side of the middle step 2 is preset according to the geological conditions on site during design.

[0041] i 1左 : The accumulated deformation of the left arch foot of the upper step 1 during the period after the steel frame 4 of the upper step 1 is installed and before the construction of the middle step 2.

[0042] i 1右 : The cumulative deformation of the right arch foot of the upper step 1 during the period after the steel frame 4 of the upper step 1 is installed and before the construction of the middle step 2.

[0043] i 2左 : After the installation of the steel frame 4 of the middle step 2 is completed and before the construction of the lower step 3, the cumulative deformation of the left arch foot of the middle step 2 during this period.

[0044] i 2右 : After the installation of the steel frame 4 of the middle step 2 is completed and before the construction of the lower step 3, the cumulative deformation of the right arch foot of the middle step 2 during this period.

[0045] S 1左 : That is, the total amount of deformation that needs to be reserved for the arch foot of the left steel frame 4 of the upper step 1 and the arch top of the left steel frame 4 of the middle step 2.

[0046] S 1右 : That is, the total amount of deformation that needs to be reserved for the arch foot of the steel frame 4 on the right side of the upper step 1 and the arch top of the steel frame 4 on the right side of the middle step 2.

[0047] S 2左 : That is, the total amount of deformation that needs to be reserved for the arch foot of the left steel frame 4 of the middle step 2 and the arch top of the left steel frame 4 of the lower step 3.

[0048] S 2右 : That is, the total amount of deformation that needs to be reserved for the arch foot of the steel frame 4 on the right side of the middle step 2 and the arch top of the steel frame 4 on the right side of the lower step 3.

[0049] When S>0, it is convergence; when S<0, it is expansion; when S=0, it is the unified prefabrication deformation in the factory.

[0050] S4: Factory prefabrication of differentiated steel frame 4: Perform reserved deformation processing on the arch foot of each steel frame 4 according to the total reserved deformation of the steel frame 4 calculated in Table 1, determine the reserved deformation of each section of the steel frame 4, and draw the processing drawings of the steel frame 4.

[0051] According to the calculated cumulative deformation, determine the reserved deformation of each section of the steel frame 4. The determination of the reserved deformation needs to consider many factors, including the geological conditions of the surrounding rock, the material properties of the steel frame 4, the construction environment, etc. After determining the reserved deformation, draw the processing drawings of the steel frame 4. The drawings should mark the size, shape and connection method of each steel frame 4 in detail to ensure that the processing plant can accurately produce it; except for the steel frame 4 on the upper step 1, the remaining steel frames 4 need to be designed separately; the steel frame 4 is prefabricated. Since the deformation of each steel frame 4 is different and the deformation is small, it is impossible to distinguish it with the naked eye, so it is necessary to affix a QR code to the bottom of the steel frame 4 after it is manufactured. The content of the QR code includes the specific position of the steel frame 4 to distinguish each steel frame 4; S5: Transportation, installation and support: During the transportation of the prefabricated steel frame 4 to the tunnel site, special attention needs to be paid to the fixation and support of the steel frame 4. A special fixing device can be installed on the transport vehicle to ensure that the steel frame 4 does not move or overturn during transportation.

[0052] S51: After arriving at the site, the steel frame 4 needs to be checked again to ensure that it is intact; because the upper and lower reserved amounts of each steel frame 4 are inconsistent, and the reserved amounts of the left and right steel frames 4 of each step are also different and difficult to distinguish with the naked eye, so before the steel frame 4 enters the hole, the workers should scan the QR code to determine the specific position of the steel frame 4, and should confirm it again before installation.

[0053] S52: Installation of steel frame 4: It should be noted that the two sections of steel frame 4 are connected by connecting steel plates and bolts, and the connecting steel plates should be tightly fitted.

[0054] When installing the steel frame 4, first use a pickaxe to carefully chisel away the concrete at the arch foot to expose the connecting steel plate and clean up the debris at the bolt holes. When the connecting steel plate is found to be deformed, the steel plate should be leveled; after the steel frame 4 is in place, several people will cooperate to erect the steel frame 4 to complete the connection and bolt tightening of the steel frame 4. The steel frame 4 should be installed perpendicular to the center line of the tunnel. The allowable deviation of the lateral spacing and elevation is ±50mm, and the allowable deviation of the verticality of the steel frame 4 is ±2 degrees; after the installation of the steel frame 4 is completed, the bolt connection should be checked again to ensure that each bolt connection is tightened without looseness.

[0055] The gap between the connecting steel plates of the two sections of the steel frame 4 should be wedged and welded firmly with steel plates. It is not allowed to use stone wedges or short steel bars for welding. The arch feet of the steel frame 4 should be arranged on a solid foundation. When the foundation strength at the arch foot is insufficient or the arch foot elevation is inaccurate, it is not allowed to backfill with hole slag or blocks of stone. Instead, concrete pads should be set for adjustment so that the arch foot is located at the designed elevation and is firm and reliable. When pouring concrete pads, the quality and strength of the concrete should be ensured to avoid instability of the steel frame 4 due to pad quality problems; the steel frame 4 should be in close contact with the wall surface, and the gap with the surrounding rock should be wedged and filled tightly with shotcrete. The subsequent steps will not be repeated in detail.

[0056] S53: According to the deformation of the steel frame 4 in the initial support, it is fed back to the precise calculation, and then the steel frame 4 of the upper step 1 is prefabricated according to the calculated total reserved deformation, so that its deformation reaches the shape of the designed section, forming a cycle: according to the deformation of the steel frame 4 in the initial support, it is fed back to the precise calculation, and the reserved deformation of each section of the steel frame 4 is recalculated. In this way, the construction plan can be continuously optimized to ensure that the deformation of the steel frame 4 is always within the controllable range. The calculated total reserved deformation is used to prefabricate the steel frame 4 of the upper step 1 so that its deformation reaches the shape of the designed section; through this cyclic adjustment, more reasonable support design and construction can be achieved.

[0057] The implementation principle of Example 1 is as follows: the excavation and support of each step section is a process of unloading and loading the surrounding rock. It is the repeated unloading and loading that causes repeated deformation of the tunnel surrounding rock. The accumulation of these repeated deformations is the composition of the reserved deformation design. It is necessary to achieve precise measurement through the use of a three-dimensional laser scanner. The three-dimensional laser scanner data analysis software "PCAS" accurately calculates the deformation value of each section of the steel frame 4. The calculated value is used to draw the steel frame 4 processing drawing and feedback it to the comprehensive processing factory for separate production and installation of each steel frame 4. Example 2

[0058] The difference between this embodiment and embodiment 1 is that composite measurement can also be combined with geological radar to further improve the accuracy and reliability of measurement. In the disclosed step S221, a three-dimensional laser scanner is used to scan each step of the tunnel during excavation to obtain point cloud data.

[0059] S2211: Combined measurement is performed with geological radar, and the point cloud data and geological radar data are imported into the 3D laser scanner data analysis software to generate a scanning cloud map of the section where the steel frame 4 is located; S2212: Compare the deformation of the same steel frame 4 section in different construction processes, and calculate the cumulative deformation of each steel frame 4 in different construction progress: By comparing the scanning cloud map of the same steel frame 4 section in different construction progress, the cumulative deformation of each steel frame 4 in different construction progress can be calculated. The key to this step is to select a suitable comparison benchmark, usually selecting the initial scan data as the benchmark, and then gradually comparing the subsequent scan data. During the calculation process, you can use the analysis tools provided by the software, or you can write a custom algorithm to improve the accuracy and efficiency of the calculation.

[0060] The implementation principle of Example 2 is as follows: the geological radar can detect the distribution of underground rock layers, provide more geological information, import the point cloud data and the geological radar data into the 3D laser scanner data analysis software, and generate a scanning cloud map of the section where the steel frame 4 is located. In this way, the geological conditions of the tunnel can be more comprehensively understood, and the accuracy and reliability of the measurement can be improved.

[0061] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method for differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel, characterized by: include S1: Tunnel excavation: Select a suitable area before excavation and excavate the specified depth in the specified area; S2: Precise measurement: The total station is set up using the rear intersection free station setting method, and a three-dimensional laser scanner is used to scan each step to obtain a large amount of point cloud data, and the cross-sectional conditions of each steel frame (4) are obtained. The cross-sectional conditions of the steel frame (4) at each construction stage are fitted to obtain the cross-sectional deformation conditions, and the deformation conditions of the steel frame (4) are obtained; S3: Analyze the deformation of the steel frame (4): The deformation of the steel frame (4) is the value obtained by subtracting the accumulated deformation from the reserved amount of the uniform prefabricated steel frame (4); S4: prefabricate the differentiated steel frame (4) in the factory: perform reserved deformation processing on the arch foot of each steel frame (4) according to the calculated total reserved deformation of the steel frame (4), determine the reserved deformation of each section of the steel frame (4), draw a processing drawing of the steel frame (4), and process the steel frame (4); S5: Transportation, installation and support: The prefabricated steel frame (4) is transported to the tunnel site and installed and initially supported.

2. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 1 is characterized by: The step S2 includes S21: Preparation before measurement: burying control points and setting up prism balls; S22: Scanning and data processing: The total station is set up using the resection free station method. The unique coordinates of the two spherical prisms are measured by the total station. A three-dimensional laser scanner is used to scan each step to obtain a large amount of point cloud data. The cross-sectional conditions of the steel frame (4) at each construction stage are fitted to obtain the cross-sectional deformation conditions. S23: Feedback on deformation: The reserved deformation of the steel frame (4) of the upper step (1) is determined according to the local geological conditions, and the remaining steel frames (4) are determined by the accumulated deformation of the steel frames (4) of the same cross section on the upper step.

3. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 1 is characterized by: In the step S3, if the deformation of the steel frame (4) is greater than zero, it is convergence; if the deformation of the steel frame (4) is less than zero, it is expansion; and if the deformation of the steel frame (4) is equal to zero, it is the same prefabricated deformation in the factory.

4. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 1 is characterized by: In step S4, the steel frame (4) is prefabricated. Since the deformation of each steel frame (4) is different and the deformation amount is small, it is impossible to distinguish them with the naked eye. Therefore, it is necessary to affix a QR code to the bottom of the steel frame (4) after it is manufactured.

5. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 1 is characterized by: In the step S5, during the transportation of the prefabricated steel frame (4) to the tunnel site, a special fixing device can be installed on the transport vehicle to ensure that the steel frame (4) will not move or overturn during transportation.

6. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 2 is characterized by: In step S2, composite measurement is performed in combination with geological radar, and the point cloud data and geological radar data are imported into the three-dimensional laser scanner data analysis software to generate a scanning cloud map of the section where the steel frame is located.

7. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 5 is characterized by: The step S5 includes S51: After arriving at the site, the steel frame (4) needs to be checked again. Before the steel frame (4) enters the hole, the workers should scan the QR code to determine the specific position of the steel frame (4), and confirm it again before installation.

8. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 7 is characterized by: The step S5 also includes S52: Installation of steel frame (4): When installing the steel frame (4), firstly, the concrete at the arch foot is carefully chiseled out manually using a cross pick to expose the connecting steel plate and clean up the debris at the bolt hole. The two sections of the steel frame (4) are connected by connecting the steel plate and bolts. The connecting steel plate should be tightly attached. The steel frame (4) should be installed in place perpendicular to the center line of the tunnel.

9. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 8 is characterized by: In step S52, when the foundation strength at the arch foot is insufficient or the arch foot elevation is inaccurate, a concrete pad should be set for adjustment, the steel frame (4) should be in close contact with the wall surface, and the gap with the surrounding rock should be wedged and filled tightly with sprayed concrete.

10. The construction method of differential reserved deformation of steel frame of expansive mud-sandstone water diversion tunnel according to claim 8 is characterized by: The step S5 also includes S53: Feedback the deformation of the steel frame (4) in the initial support to the precise calculation, and then prefabricate the steel frame (4) of the upper step (1) according to the total reserved deformation obtained by calculation so that its deformation reaches the shape of the designed section, forming a cycle.

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