Method for rapidly constructing underground space under existing roads

Abstract

A method for quickly constructing an underground space under an existing road, where there is a green belt in the center of the existing road, comprising step 1: driving retaining piles or diaphragm walls from the ground outside the underground space structure; step 2: constructing steel pipe piles and their steel pipe column foundations in the green belt in the center of the existing road; step 3: constructing temporary vertical shafts in the green belt in the center of the road; step 4: constructing pipe curtain working wells on both sides of the ground; step 5: driving pipe curtains in the pipe curtain working wells; step 6: after the pipe curtain construction is completed, constructing pile top capping beams in the pipe curtain working wells and top longitudinal beams above the intermediate columns in the temporary vertical shafts; step 7: backfilling the foundation pits of the pipe curtain working wells and temporary vertical shafts; step 8: under the protection of the combined support, carrying out the construction of the underground space structure; thus, the method of the present invention does not break or cover the road, does not affect ground traffic, nor does it require pipeline relocation, has no mined pilot tunnels, has a fast construction speed and a low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of underground space construction, and in particular to a method for quickly constructing an underground space under an existing road by the top-down construction method without covering the road, without affecting the ground traffic, without relocating municipal pipelines, and without setting up pilot tunnels for mined tunneling. Background Art

[0002] With the vigorous development of underground spaces such as urban rail transit, utility tunnels, and underground commercial streets, especially when the urban rail transit network is densified, it is necessary to construct underground projects under existing road conditions without affecting the ground traffic. Therefore, pipeline relocations and road covering are not allowed, and at the same time, the construction period is fast and the investment is saved.

[0003] Therefore, in view of the above defects, the designers of the present invention, through painstaking research and design, combined with the experience and achievements in engaging in related industries for many years, have studied and designed a method for quickly constructing an underground space under an existing road to overcome the above defects. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for quickly constructing an underground space under an existing road, which does not cover the road, does not affect the ground traffic, does not require pipeline relocations, has no pilot tunnels for mined tunneling, has a fast construction speed, and a low cost.

[0005] To achieve the above purpose, the present invention discloses a method for quickly constructing an underground space under an existing road, wherein there is a green belt in the center of the existing road, and the method is characterized by including the following steps:

[0006] Step 1: Drive retaining piles or diaphragm walls from the ground outside the underground space structure;

[0007] Step 2: Construct steel pipe piles and their steel pipe column foundations in the green belt in the center of the existing road;

[0008] Step 3: Construct a temporary shaft in the green belt in the center of the road, construct a collar beam, excavate the soil and erect steel grids, and make the bottom elevation of the temporary shaft foundation pit flush with the bottom elevation of the top longitudinal beam;

[0009] Step 4: Construct pipe curtain working wells on both sides of the ground, and the pipe curtain working wells are lower than the bottom elevation of the capping beam;

[0010] Step 5: Drive a pipe curtain in the pipe curtain working well, place one end of the pipe curtain in the reserved top longitudinal beam in the temporary shaft, and place one end of the pipe curtain in the top longitudinal beam for not less than 500 mm, and fill the pipe curtain with cement mortar or fine aggregate concrete;

[0011] Step 6: After the pipe roof construction is completed, construct the pile top capping beam in the pipe roof working shaft, and construct the top longitudinal beam above the middle column in the temporary shaft. The concrete is poured densely. One end of the pipe roof is restrained in the top longitudinal beam, and the other end of the pipe roof is placed in the capping beam and is placed in the capping beam not less than 500 mm;

[0012] Step 7: Backfill the foundation pits of the pipe roof working shaft and the temporary shaft;

[0013] Step 8: Under the protection of the combined support composed of the pipe roof, retaining piles or diaphragm walls, capping beams and top longitudinal beams, construct the underground space structure.

[0014] Among them: It also includes Step 9: After the underground space structure construction is completed, demolish the pipe roof working shaft and the temporary shaft below 3.0 m below the ground, and construct the underground space auxiliary structure according to the underground space requirements.

[0015] Among them: The construction of the underground space structure in Step 8 is specifically as follows: When excavating the soil downward to 500 mm below the first internal support, construct the first internal support. When continuing to excavate the soil downward to 500 mm below the second internal support, construct the second internal support. When excavating the remaining soil to the bottom elevation of the floor slab, construct the floor slab, construct the side walls of the second basement floor, construct the middle slab, construct the side walls of the first basement floor, and construct the top slab.

[0016] Among them: When the span of the underground space is large and the stiffness of the pipe roof is insufficient, insert steel bars or steel strands into the steel pipes of the pipe roof, and the steel bars or steel strands are anchored into the pile top capping beam of the retaining pile or diaphragm wall and the top longitudinal beam of the middle column to increase the overall stiffness of the pipe roof.

[0017] Among them: The diameter of the pipe roof is 108 mm to 1000 mm.

[0018] Among them: The pipe roof includes multiple steel pipes fixedly connected. One end of the pipe roof is provided with a female locking buckle, and the other end is provided with a male locking buckle that can be buckled and locked with the female locking buckle, so that multiple pipe roofs can meet different requirements through the cooperation and locking of the male and female locking buckles.

[0019] Among them: In Step 6, through the pile top capping beam and the top longitudinal beam, the two ends of the pipe roof are respectively restrained in the top longitudinal beam and the capping beam to form a combined support system;

[0020] The specific construction method is as follows:

[0021] Pre-drilling construction: Before installing the pipe curtain, pre-drilling construction is carried out first. According to the designed position and diameter of the pipe curtain, a pilot hole is drilled using a geological drill. The function of the pilot hole is to provide accurate guidance for the installation of the pipe curtain, reducing the deviation during the installation process. During the drilling of the pilot hole, total stations and gyroscopes and other surveying equipment are also used for real-time monitoring to ensure the accuracy of the pilot hole. After the completion of the pilot hole, the pipe curtain is installed into the pilot hole by jacking or drilling methods, effectively improving the construction accuracy of the pipe curtain;

[0022] Segmented construction and measurement review: The pipe curtain construction is divided into several segments. After the completion of each segment of construction, a comprehensive measurement review is carried out. At the joints of each segment of the pipe curtain, high-precision surveying instruments are used to measure the docking deviation of the pipe curtain, including axial deviation and radial deviation.

[0023] Among them: Step 2 also includes:

[0024] Pre-construction preparation:

[0025] Accurate measurement and layout: The construction site is comprehensively measured using a high-precision total station. According to the design drawings, the positions and axes of the steel pipe piles are accurately marked, obvious control points and control lines are set, and multiple reviews are carried out to ensure the accuracy of the layout;

[0026] Construction process control:

[0027] Set up guiding devices: Guiding clamps are set on the top of the steel pipe piles and on the pile frames to provide real-time guidance for the steel pipe piles during the piling process, preventing them from shifting and tilting during driving;

[0028] Real-time monitoring: A total station is used for real-time monitoring during the piling process. The verticality and position deviation of the steel pipe piles are measured at regular intervals. Once the deviation exceeds the allowable range, adjustments are immediately made;

[0029] Post-construction inspection:

[0030] Pile formation inspection: After the piling is completed, ultrasonic testing, core drilling and other methods are used to comprehensively detect the verticality and position accuracy of the steel pipe piles. For piles that do not meet the requirements, remedial measures are taken in a timely manner, such as rectifying or adding piles.

[0031] Among them: In step 3, layered and segmented excavation is adopted. The specific excavation steps are as follows:

[0032] First-layer excavation: Starting from the wellhead, according to the designed layered thickness, first excavate the middle part of the shaft, and then gradually expand to the periphery to form a pot-bottom shape;

[0033] Install supports: After the first-layer excavation is completed, steel supports or shotcrete linings are installed on the shaft wall to reinforce the shaft wall and prevent the shaft wall from collapsing;

[0034] Excavation of the second layer and below: Repeat the excavation and support operations of the first layer until the designed depth is reached.

[0035] Among them: In step 5, high-performance cement is used as the cementitious material for the filling material, while quartz sand is selected as the fine aggregate, and an appropriate amount of water reducer and expansion agent are added to the filling material;

[0036] The pouring process adopts the high-pressure jet grouting technology: During the filling process of the pipe curtain, the high-pressure jet grouting process is adopted, and it is poured in sections and layers: According to the length and diameter of the pipe curtain, the pipe curtain is divided into several sections, and the method of pouring in sections and layers is used for filling.

[0037] As can be seen from the above, the method for quickly constructing an underground space under an existing road of the present invention has the following effects:

[0038] 1. When there is a green belt in the center of the existing road or when there are conditions for constructing a temporary construction shaft in the center and conditions for constructing pipe curtain working wells on both sides of the existing road, a retaining pile or diaphragm wall and a pipe curtain support system can be formed, and there is no need to relocate pipelines and break and cover the road, and the underground space structure can be directly constructed.

[0039] 2. The underground space structure is constructed under the support of the retaining pile or diaphragm wall and the pipe curtain, and there are permanent steel pipes and their steel pipe foundations in the central green belt of the road or in the center, and an arch structure can be formed, with good stress, and the underground space structure can be constructed without setting up a mined pilot tunnel.

[0040] 3. Compared with mined construction, there is no need to construct a mined pilot tunnel, and the construction speed of this method is significantly accelerated and the cost is greatly reduced.

[0041] The detailed content of the present invention can be obtained through the following description and the accompanying drawings. Description of the Drawings

[0042] Figure 1 Shows a schematic diagram of the method for quickly constructing an underground space under an existing road of the present invention.

[0043] Figure 2 Shows a schematic diagram of the pipe curtain connection structure in the present invention.

[0044] Reference Signs:

[0045] 1. Ground surface, 2. Pipe roof working shaft, 3. Locking ring beam, 4. Pipe roof, 5. Crown beam, 6. Retaining pile, 7. Underground space structure, 8. Underground pipeline, 9. Roof slab, 10. Side wall of the first basement floor, 11. Middle slab, 12. Side wall of the second basement floor, 13. Floor slab, 14. Top longitudinal beam, 15. Steel pipe pile, 16. Middle longitudinal beam, 17. Bottom longitudinal beam, 18. Steel pipe column foundation, 19. Temporary shaft, 20. Retaining wall, 21. First internal support, 22. Second internal support, 40. Steel pipe, 41. Female locking buckle, 42. Male locking buckle. Detailed implementation method

[0046] Refer to Figure 1 and 2 , which shows the method for quickly constructing an underground space under an existing road, where there is a green belt in the center of the existing road or there are conditions for constructing pile foundations in the center.

[0047] The method for quickly constructing an underground space under an existing road may include the following steps:

[0048] Step 1: Outside the underground space structure 7, the underground space structure 7 is a columned space structure. Drive retaining piles 6 or diaphragm walls from the ground surface 1. The clear distance between the retaining piles 6 or diaphragm walls and the underground space structure 7 is preferably 100 mm. According to the construction machinery and construction technology level, the gap between the retaining pile and the structure can be appropriately enlarged to avoid the retaining pile invading the underground space structure 7 after the foundation pit is excavated.

[0049] Step 2: Construct steel pipe piles 15 and their steel pipe column foundations 18 in the green belt in the center of the existing road. Among them, the steel pipe piles 15 and their steel pipe column foundations 18 form the permanent columns and pile foundations of the underground space structure 7, which are located in the middle position of the underground space structure.

[0050] Step 3: Construct a temporary shaft 19 in the green belt in the center of the road, construct a locking ring beam 3, excavate the soil body and erect steel grids. The bottom elevation of the foundation pit of the temporary shaft 19 is flush with the bottom elevation of the top longitudinal beam 14.

[0051] Step 4: Construct pipe roof working shafts 2 on both sides of the ground surface 1. The pipe roof working shafts 2 are lower than the bottom elevation of the crown beam 5. Optionally, the distance from the bottom of the shallow foundation pit in the open space on both sides of the road to the lower part of the pipe roof construction distance is not less than 0.5 m, and the pipe shed construction space should be satisfied.

[0052] Step 5: Drive a pipe roof 4 in the pipe roof working shaft 2, place one end of the pipe roof in the reserved top longitudinal beam in the temporary shaft 19, and place one end of the pipe roof in the top longitudinal beam 14 for not less than 500 mm. Fill the pipe roof with cement mortar or fine aggregate concrete. The preferred pipe roof diameter is 108 mm to 1000 mm. The pipe roof diameter and other parameters can be reasonably determined according to conditions such as the underground space span and the upper load.

[0053] Step 6: After the construction of the pipe roof 4 is completed, construct the pile top capping beam 5 in the pipe roof working shaft 2, and construct the top longitudinal beam 14 above the intermediate column in the temporary shaft. The concrete is poured densely. One end of the pipe roof is restrained in the top longitudinal beam 14, and the other end of the pipe roof 4 is placed in the capping beam 5 and is placed in the capping beam 5 not less than 500 mm.

[0054] In this step, by first constructing the pile top capping beam 5 and the top longitudinal beam 14, and then restraining the two ends of the pipe roof in the top longitudinal beam 14 and the capping beam 5 respectively, a combined support system is formed. When constructing the pipe roof in the pipe roof working shaft 2, it is difficult to ensure the construction accuracy of the pipe roof, and high-precision measurement and driving equipment are required. At the same time, it is necessary to ensure the anchorage depth of the pipe roof in the top longitudinal beam and the capping beam. By forming a combined support system composed of the retaining piles 6 or diaphragm walls and the pipe roof 4, the vertical load above the underground space can be directly borne, avoiding the relocation of pipelines and the breaking and covering of roads, reducing the impact of construction on the surrounding environment, and reducing the construction cost and construction period.

[0055] Among them, to ensure high-precision measurement, the high-precision measurement equipment used is a total station and a gyroscope. Before construction, use the total station to accurately measure the coordinates of the pipe roof working shaft and establish a high-precision measurement control network. During the driving process of the pipe roof, the position deviation of the pipe roof is monitored in real time by the total station. The total station is set up on a stable control point, and the measurement target at the front end of the pipe roof is observed. Multiple observation points are set on the measurement target, which can accurately measure the deviation of the pipe roof in the horizontal and vertical directions. According to the measurement data, the angle and propulsion direction of the pipe roof driving equipment are adjusted in time to ensure that the pipe roof is driven according to the design track.

[0056] Moreover, by installing a high-precision gyroscope inside the pipe roof, the gyroscope can monitor the inclination angle and azimuth change of the pipe roof in real time. Since the gyroscope is not affected by external magnetic field and other factors, the measurement accuracy is high. During the driving process of the pipe roof, the gyroscope transmits the measurement data to the ground monitoring system in real time. Once the pipe roof is inclined or the azimuth deviates, the system immediately issues an alarm, and the operator can adjust the driving equipment accordingly to ensure the verticality and azimuth accuracy of the pipe roof.

[0057] Among them, the advanced driving equipment used includes a guided drill and a pipe jacking machine. The guided drill with a high-precision guiding function is used for driving the pipe roof. The guided drill is equipped with an advanced guiding system. By installing a probe at the front end of the drill bit, parameters such as the position, angle, and depth of the drill bit are measured in real time. These parameters are fed back to the operation control console of the drill through wireless transmission or wired transmission. The operator accurately controls the drilling direction and propulsion speed of the drill according to the feedback data. The guided drill can also automatically adjust the drilling parameters according to different geological conditions to ensure that the pipe roof can be accurately driven under complex geological conditions.

[0058] Pipe jacking machine: For some pipe curtains with larger diameters, a pipe jacking machine is used for construction. The pipe jacking machine is equipped with a high-precision jacking system and a deviation correction device. During the jacking process, through sensors installed at the tail of the pipe jacking machine, the jacking direction and jacking force of the pipe jacking machine are monitored in real time. When the pipe jacking machine deviates, the deviation correction device can be quickly activated, and by adjusting the attitude of the pipe jacking machine, the pipe curtain can be returned to the correct design trajectory. The jacking speed and jacking force of the pipe jacking machine can also be precisely controlled to ensure the construction quality and accuracy of the pipe curtain.

[0059] The specific construction method is as follows:

[0060] Pre-drilling construction: Before installing the pipe curtain, pre-drilling construction is carried out first. According to the design position and diameter of the pipe curtain, a geological drill is used to drill a pilot hole. The role of the pilot hole is to provide accurate guidance for the installation of the pipe curtain and reduce the deviation during the installation process of the pipe curtain. During the drilling process of the pilot hole, total stations and gyroscopes and other measuring equipment are also used for real-time monitoring to ensure the accuracy of the pilot hole. After the pilot hole is completed, the pipe curtain is installed into the pilot hole by jacking or drilling methods, effectively improving the construction accuracy of the pipe curtain.

[0061] Segmented construction and measurement review: The pipe curtain construction is divided into several segments. After each segment of construction is completed, a comprehensive measurement review is carried out. At the joints of each segment of the pipe curtain, high-precision measuring instruments are used to measure the docking deviation of the pipe curtain, including axial deviation and radial deviation. If the deviation exceeds the allowable range, adjustments are made in a timely manner. Through segmented construction and measurement review, deviations during the construction process can be discovered and corrected in a timely manner, ensuring the construction accuracy of the entire pipe curtain.

[0062] Thus, through the above specific steps and equipment, the specially set joint support system in the present invention is realized to effectively bear the vertical load above the underground space.

[0063] Step 7: Backfill the foundation pits of the pipe curtain working well 2 and the temporary shaft 19.

[0064] Step 8: Under the protection of the joint support composed of the pipe curtain 4, the retaining pile 6 or the diaphragm wall, the capping beam 5 and the top longitudinal beam 14, the construction of the underground space structure 7 is carried out. Specifically, the earthwork can be excavated downward to 500 mm below the first internal support 21, and the first internal support 21 is constructed. Then, the earthwork is continuously excavated downward to 500 mm below the second internal support 22, and the second internal support 22 is constructed. When the remaining soil is excavated to the bottom elevation of the floor slab 13, the floor slab 13 is constructed, the side wall 12 of the second basement floor is constructed, the middle slab 11 is constructed, the side wall 10 of the first basement floor is constructed, and the top slab 9 is constructed.

[0065] Step 9: After the construction of the underground space structure 7 is completed, the pipe curtain working well 2 and the temporary shaft 19 below 3.0 m below the ground surface are demolished, and the underground space auxiliary structure is constructed according to the underground space requirements.

[0066] Among them, in Step 2:

[0067] Since it is necessary to ensure the verticality and position accuracy of the steel pipe piles and the foundation, it is necessary to reasonably plan the construction site, set up a material stacking area and an equipment parking area; adopt advanced measurement and positioning technologies such as total station positioning, etc.

[0068] Pre-construction preparation:

[0069] Precise measurement and setting out: Use a high-precision total station to conduct a comprehensive measurement of the construction site, accurately mark the positions and axes of the steel pipe piles according to the design drawings, set obvious control points and control lines, and conduct multiple reviews to ensure the accuracy of setting out.

[0070] Equipment calibration: Conduct a comprehensive inspection and calibration of the pile driving equipment, especially the verticality adjustment device of the pile frame and the guiding device of the pile hammer, to ensure that the equipment can operate normally during construction and ensure the verticality and position accuracy of pile driving.

[0071] Construction process control:

[0072] Set up a guiding device: Set up guiding jigs on the top of the steel pipe pile and the pile frame to conduct real-time guidance on the steel pipe pile during pile driving to prevent it from shifting and tilting during driving.

[0073] Real-time monitoring: Use a total station to conduct real-time monitoring during pile driving, measure the verticality and position deviation of the steel pipe pile every certain period of time (such as every 1 meter driven), and immediately make adjustments once the deviation exceeds the allowable range.

[0074] Control the pile driving sequence: According to the site geological conditions and the distribution of pile positions, reasonably determine the pile driving sequence to avoid mutual extrusion and deviation between adjacent piles due to improper pile driving sequence, which affects the verticality and position accuracy of the piles.

[0075] Post-construction inspection:

[0076] Pile formation detection: After pile driving is completed, use methods such as ultrasonic testing and core drilling to conduct a comprehensive detection of the verticality and position accuracy of the steel pipe piles. For piles that do not meet the requirements, take remedial measures in a timely manner, such as rectifying or adding piles.

[0077] Thus, it can provide stable permanent columns and pile foundations for the underground space structure.

[0078] In Step 3, layered and segmented excavation is adopted, and the specific excavation steps are as follows:

[0079] First-layer excavation: Starting from the wellhead, using a small excavator, excavate according to the designed layer thickness (usually 2 - 3 meters). First, excavate the middle part of the shaft, and then gradually expand to the periphery to form a pot-bottom shape. During the excavation process, trim the shaft wall while excavating to keep it approximately vertical.

[0080] Installation of supports: After the first-layer excavation is completed, promptly install steel supports or spray concrete linings on the shaft wall to reinforce the shaft wall and prevent it from collapsing. The spacing and form of the supports are determined according to the design requirements and geological conditions.

[0081] Second-layer and subsequent excavations: Repeat the excavation and support operations of the first layer until the designed depth is reached. During each layer of excavation, strictly control the excavation depth and the verticality of the shaft wall. For every 1 - 2 meters of excavation, use surveying instruments (such as a laser plumb bob) to measure the verticality of the shaft wall, and adjust promptly when deviations are found.

[0082] Manual trimming: When each layer of excavation is approaching the designed depth, perform fine trimming manually to ensure that the shaft wall is flat and vertical, and the bottom is flat, meeting the design requirements.

[0083] Use advanced earth excavation equipment, such as a small excavator in cooperation with manual trimming.

[0084] Thus, provide a working space for the subsequent pipe curtain construction.

[0085] In step 5, use high-precision pipe curtain driving equipment, such as a guided drilling rig; strictly control the mix ratio and pouring process of the filling material.

[0086] The raw materials in the filling material are selected as follows: Use a new type of high-performance cement as the cementitious material, which has characteristics such as high early strength and good stability. At the same time, select well-graded quartz sand as the fine aggregate, which has regular particle shapes and smooth surfaces, and can improve the fluidity and compactness of the filling material.

[0087] Addition of admixtures: Add appropriate amounts of water-reducing agents and expansion agents to the filling material. The water-reducing agent can effectively reduce the water-cement ratio, improve the strength and durability of the filling material, and at the same time increase its fluidity for convenient pouring construction. The expansion agent can compensate for the shrinkage of the filling material during the hardening process, prevent cracks from occurring, and improve the compactness of the filling.

[0088] Mix ratio test and optimization: Through a large number of laboratory tests, according to different underground space conditions and design requirements, determine the optimal mix ratio of the filling material. Use the orthogonal experimental design method to systematically study the effects of factors such as water-cement ratio, sand ratio, and admixture dosage on the performance of the filling material, establish a relationship model between the mix ratio and performance, and thus optimize the best mix ratio that meets the project requirements.

[0089] The pouring process adopts the high-pressure jet grouting technology: during the filling process of the pipe curtain, the high-pressure jet grouting process is used. Through the high-pressure jet equipment, the filling material prepared according to the mix ratio is injected into the pipe curtain in the form of a high-pressure jet, so that the filling material is fully mixed with the inner wall of the pipe curtain and the surrounding soil mass and densely filled. The high-pressure jet grouting technology can effectively improve the density and uniformity of the filling material and enhance the overall performance of the pipe curtain.

[0090] Segmented and layered pouring: According to the length and diameter of the pipe curtain, the pipe curtain is divided into several segments, and the method of segmented and layered pouring is used for filling. When pouring each segment, start from the bottom of the pipe curtain and gradually pour upwards. The pouring thickness of each layer is controlled within a certain range (such as 30 - 50 cm) to ensure that the filling material is evenly and densely packed under the action of gravity.

[0091] Real-time monitoring and quality control: During the pouring process, ultrasonic detectors and other equipment are used to monitor the filling quality in real time. By detecting indicators such as the density and uniformity of the filling material, problems existing in the pouring process, such as cavities and segregation, can be discovered in a timely manner. Once quality problems are found, the pouring is immediately stopped, and corresponding treatment measures are taken, such as injecting additional filling material and adjusting the pouring process, to ensure that the filling quality of the pipe curtain meets the design requirements.

[0092] Thus, an effective support structure is formed to improve the stability of the underground space structure.

[0093] Furthermore, if the span of the underground space is large and the stiffness of the pipe curtain is insufficient, when excavating the soil downwards, steel bars or steel strands can be inserted into the steel pipes of the pipe curtain, and the steel bars or steel strands are anchored into the pile top capping beam of the retaining pile or diaphragm wall and the longitudinal beam at the top of the middle column to increase the overall stiffness of the pipe curtain. Of course, if the stiffness of the pipe curtain meets the requirements, it is not necessary to insert steel bars or steel strands into the steel pipes of the pipe curtain.

[0094] Among them, as Figure 2 shown, the pipe curtain 4 includes multiple fixedly connected steel pipes 40. One end of the steel pipe 40 is provided with a female locking buckle 41, and the other end is provided with a male locking buckle 42 that can be buckled and locked with the female locking buckle 41. Thus, multiple pipe curtains 4 can meet the requirements of different widths through the cooperation and locking of the male locking buckle 42 and the female locking buckle 41.

[0095] Obviously, the above description and record are only examples and not intended to limit the disclosure, application or use of the present invention. Although it has been described in the embodiments and illustrated in the drawings, the present invention does not limit the specific examples described in the embodiments and illustrated in the drawings as the currently considered best mode for implementing the teachings of the present invention. The scope of the present invention will include any embodiments falling within the foregoing description and the appended claims.

Claims

1. A method for quickly constructing an underground space under an existing road, wherein there is a green belt in the middle of the existing road, characterized in that The following steps are included: Step 1: Drive retaining piles or underground continuous walls from the ground outside the underground space structure; Step 2: Construct steel pipe piles and their steel pipe column foundations in the green belt in the middle of the existing road; Step 3: Construct a temporary shaft in the central green belt of the road, construct a locking ring beam, excavate the soil and set up a steel grid. The bottom of the temporary shaft foundation pit is flush with the bottom elevation of the top longitudinal beam; Step 4: Construct pipe curtain working wells on both sides of the ground. The pipe curtain working wells are lower than the bottom elevation of the crown beam; Step 5: Install the pipe curtain in the pipe curtain working shaft, and place one end of the pipe curtain in the reserved top longitudinal beam in the temporary shaft, with one end of the pipe curtain placed in the top longitudinal beam by no less than 500mm, and fill the pipe curtain with cement mortar or fine stone concrete; Step 6: After the pipe curtain construction is completed, the pile top crown beam is constructed in the pipe curtain working shaft, and the top longitudinal beam above the middle column is constructed in the temporary shaft. The concrete is poured densely, one end of the pipe curtain is restrained in the top longitudinal beam, and the other end of the pipe curtain is placed in the crown beam, and the distance inside the crown beam is not less than 500mm; Among them, through the pile top crown beam and top longitudinal beam, the two ends of the pipe curtain are respectively constrained in the top longitudinal beam and the crown beam to form a joint support system; The specific construction method is: Pre-drilling construction: Before the pipe curtain is installed, pre-drilling construction is carried out. According to the designed position and diameter of the pipe curtain, a geological drill is used to drill a pilot hole. The role of the pilot hole is to provide precise guidance for the installation of the pipe curtain and reduce the deviation of the pipe curtain during the installation process. During the drilling of the pilot hole, measuring equipment such as a total station and a gyroscope are also used for real-time monitoring to ensure the accuracy of the pilot hole. After the pilot hole is completed, the pipe curtain is installed in the pilot hole by jacking or drilling, which effectively improves the accuracy of the pipe curtain construction; Sectional construction and measurement review: The pipe curtain construction is divided into several sections. After each section is completed, a comprehensive measurement review is carried out. At the joint of each section of the pipe curtain, high-precision measuring instruments are used to measure the pipe curtain docking deviation, including axial deviation and radial deviation; Step 7: Backfill the pipe curtain working pit and temporary shaft foundation pit; Step 8: Under the protection of the combined support consisting of pipe curtains, retaining piles or underground continuous walls, cap beams and top longitudinal beams, the underground space structure is constructed.

2. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: It also includes step 9: after the construction of the underground space structure is completed, the pipe curtain working shaft and temporary shaft 3.0m below the ground are dismantled, and the underground space auxiliary structure is constructed according to the needs of the underground space.

3. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: The construction of the underground space structure in step 8 is specifically as follows: when the earth is excavated downward to 500mm below the first internal support, the first internal support is constructed; when the earth is continued to be excavated downward to 500mm below the second internal support, the second internal support is constructed; when the remaining soil is excavated to the bottom elevation of the bottom plate, the bottom plate is constructed, the side wall of the second underground floor is constructed, the middle plate is constructed, the side wall of the first underground floor is constructed, and the top plate is constructed.

4. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: When the span of the underground space is large and the rigidity of the pipe curtain is insufficient, steel bars or steel strands are inserted into the steel pipes of the pipe curtain. The steel bars or steel strands are anchored into the top crown beams of the retaining piles or underground continuous wall piles and the top longitudinal beams of the central columns to increase the overall rigidity of the pipe curtain.

5. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: The diameter of the pipe curtain is 108mm~1000mm.

6. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: The pipe curtain comprises a plurality of fixedly connected steel pipes, a female lock buckle is provided at one end of the pipe curtain, and a male lock buckle which can be buckled and locked with the female lock buckle is provided at the other end, so that a plurality of pipe curtains can achieve different requirements through the matching lock buckles of the male lock buckle and the female lock buckle.

7. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: Step 2 also includes: Preparation before construction: Accurate measurement and layout: Use a high-precision total station to conduct a comprehensive measurement of the construction site, accurately mark the position and axis of the steel pipe piles according to the design drawings, set obvious control points and control lines, and conduct multiple reviews to ensure the accuracy of the layout; Construction process control: Setting up guiding devices: Setting up guiding fixtures on the top of the steel pipe pile and the pile frame to guide the steel pipe pile in real time during the piling process to prevent it from deflecting and tilting during the driving process; Real-time monitoring: Use a total station to conduct real-time monitoring during the piling process, measure the verticality and position deviation of the steel pipe piles at regular intervals, and make adjustments immediately if the deviation exceeds the allowable range; Post-construction inspection: Pile testing: After the piling is completed, ultrasonic testing, core drilling and other methods are used to conduct a comprehensive test on the verticality and position accuracy of the steel pipe piles. For piles that do not meet the requirements, remedial measures are taken in a timely manner, such as correcting the deviation or adding piles.

8. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: In step 3, layered and segmented excavation is adopted, and the specific excavation steps are as follows: First layer excavation: starting from the wellhead, excavate the middle part of the shaft first according to the layer thickness required by the design, and then gradually expand to the periphery to form a pot bottom shape; Erection of support: After the first layer of excavation is completed, steel support or shotcrete wall is installed on the shaft wall to reinforce the shaft wall and prevent the shaft wall from collapsing; Excavation of the second layer and below: Repeat the excavation and support operations of the first layer until the excavation reaches the designed depth.

9. The method for rapidly constructing an underground space under an existing road as claimed in claim 1, characterized in that: In step 5, high-performance cement is used as the cementitious material for the filling material, and quartz sand is selected as the fine aggregate, and an appropriate amount of water reducing agent and expansion agent are added to the filling material; The pouring process adopts high-pressure rotary jet grouting technology: During the pipe curtain filling process, high-pressure rotary jet grouting technology is adopted, and the pouring is carried out in sections and layers: According to the length and diameter of the pipe curtain, the pipe curtain is divided into several sections, and the filling is carried out by section and layer pouring method.

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