Comprehensive isolating and reinforcing structure of water-permeable soft stratum shield short-distance side penetrating high-speed rail bridge pile

Abstract

The utility model discloses a comprehensive isolating and reinforcing structure of a water-permeable soft stratum shield close-distance side penetrating high-speed rail bridge pile. The comprehensive isolating and reinforcing structure comprises a cast-in-situ bored pile, a TRD construction method wall and a sleeve valve pipe grouting area. The cast-in-situ bored piles serve as isolation piles and are distributed on the left side and the right side of the uplink tunnel and the left side and the right side of the downlink tunnel correspondingly. The TRD construction method wall is arranged on the outer side of the cast-in-situ bored pile; according to the comprehensive isolating and reinforcing structure suitable for the shield short-distance side-penetrating high-speed rail bridge pile of the water-permeable soft stratum, the disturbance influence of shield tunneling on the stratum is reduced, the stability of a high-speed rail pile foundation is enhanced, and the comprehensive isolating and reinforcing structure is suitable for the situation that the hoisting operation height of construction adjacent to the high-speed rail pile foundation is limited. And aiming at the characteristics of high water content and low adhesive strength of the permeable soft stratum, the influence of shield construction on settlement and displacement of the existing high-speed rail bridge pile is reduced to the greatest extent by a grouting, drilling and grouting isolation pile and TRD construction method wall comprehensive isolation reinforcing structure, and the safety of construction and high-speed rail train running is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of underground space construction, in particular to a comprehensive isolation and reinforcement structure for a shield machine in a permeable soft stratum that passes through a high-speed railway bridge pile at a close distance. Background Art

[0002] With the development of urban rail transit construction in China, subway shield construction often needs to cross existing structures at close range. Subway shield construction may cause stratum loss and cause the movement of surrounding soil. This soil displacement will cause additional internal forces and deformation in the pile foundation of the existing structure. In urban rail transit projects, high-speed rail is a special existing structure. Due to the high speed of high-speed rail trains, the control of track deformation is extremely high. Once the high-speed rail pile foundation is affected, it may cause the deformation of the track structure on the high-speed rail bridge, thereby aggravating the unevenness of the track. In severe cases, it may even affect the normal operation of the high-speed railway or cause damage to the pile foundation and bridge structure. Therefore, it is very important to ensure the construction safety of the shield tunnel when it passes through the pile foundation of the high-speed rail bridge at close range.

[0003] Traditional bored pile isolation structures have large lateral displacements due to the presence of silty clay, medium-coarse sand and other permeable soft strata in the permeable soft strata. The impact range of soil disturbance and the lateral friction loss of bored piles during shield tunneling are large. Bored piles are prone to lateral displacement, which leads to damage to the isolation structure and affects the settlement and displacement of the high-speed railway pile foundation. Traditional water-stop designs such as jet grouting piles, biaxial and triaxial cement mixing piles require higher working surfaces and lifting machinery, and are not suitable for shield tunneling close to the high-speed railway pile foundation.

[0004] Traditional isolation and reinforcement schemes are now unable to meet the current technical requirements for shield construction in permeable soft strata with close side penetration of high-speed railway pile foundations, and the water-proofness of the isolation and reinforcement structure is difficult to ensure. There is an urgent need for an isolation and reinforcement structure that does not require a high construction working surface and can reduce the friction loss on the side of the cast-in-place piles and improve the water-proofness, so as to ensure the safety of shield construction and the stability of high-speed railway bridge piles. Utility Model Content

[0005] The utility model provides a comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum that is close to the side of a high-speed railway bridge pile, aiming to solve the deficiencies in the above-mentioned prior art and proposing a grouting + bored cast isolation pile--++TRD method wall comprehensive isolation and reinforcement structure, which solves the problem of height restriction for construction operations and improves the safety of the shield tunneling construction that is close to the side of a high-speed railway bridge pile, as well as the strength of the soil and the water-isolating performance.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a comprehensive isolation and reinforcement structure for a shield tunnel in permeable soft strata to pass through high-speed railway bridge piles at close range is designed; a TRD construction wall is set below the high-speed railway line, 2m on both sides of the tunnel outer contour, and about 9.5 meters beyond the high-speed railway pedestal pile foundation in the excavation direction; the TRD construction wall adopts P.042.5 grade ordinary Portland cement, with a cement content of 25%, a water-cement ratio of 1.5, and excavation fluid mixed with nano bentonite; these materials and proportions ensure the stability and quality of the soil during the TRD construction process.

[0007] Furthermore, the TRD construction method wall vertically reaches 5m below the bottom plate of the shield tunnel to form a 0.6-meter thick water-stop structure.

[0008] Furthermore, a row of φ1m@1.2m bored cast-in-place isolation piles are driven 1m along the outer contours of the upper and lower tunnels. These isolation piles extend about 9.5m beyond the high-speed railway bridge piles in the plane along the tunnel excavation direction and extend vertically to 5m below the tunnel floor. To ensure precise construction, the pile position deviation of the bored piles is controlled to not exceed 20mm and the verticality is kept within 0.5%.

[0009] Furthermore, the sleeve valve pipe adopts a galvanized grouting inner pipe and a PVC grouting outer pipe, with a size of φ50×5mm.

[0010] Furthermore, the sleeve valve pipes are arranged between the isolation ranges of two rows of bored cast-in-place piles according to a row spacing and pipe spacing of 1.2m to 1.3m.

[0011] Furthermore, the left and right reinforcement range of the sleeve valve pipe grouting area is located between two rows of bored piles, and the upper and lower range is located from 3 meters above the shield tunnel arch to 2 meters below the tunnel floor.

[0012] Furthermore, in order to ensure that the water-stopping structure of the TRD method wall is not affected by pile erosion, the TRD method wall is constructed before the bored cast-in-place piles.

[0013] Furthermore, in order to avoid the collapse of the boreholes near the bridge piles, steel casing simple retaining wall drilling construction is adopted.

[0014] The utility model has at least the following beneficial effects:

[0015] Enhanced construction safety: A comprehensive isolation reinforcement structure of grouting, bored cast-in-place isolation piles and TRD method wall was introduced. This design takes into account the characteristics of permeable soft strata, can effectively reduce the side friction loss of cast-in-place piles, and improve the water-isolating performance, thus ensuring the construction safety of the shield when it passes through the high-speed railway bridge pile foundation at close range;

[0016] Improve the stability of high-speed rail pile foundation: Due to the high requirements of high-speed rail on track structure deformation, this structural design can effectively control the movement of the stratum and avoid the stratum disturbance caused by shield construction, thereby preventing damage to the pile foundation and bridge structure, ensuring the normal operation of the high-speed rail and the smoothness of the track;

[0017] Adapting to the technical requirements of shield short-distance side-penetration construction: This new type of comprehensive reinforcement structure does not require a higher working surface and lifting machinery, and is more suitable for shield short-distance side-penetration construction, improving construction efficiency and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic plan view of the comprehensive isolation and reinforcement structure proposed by the utility model;

[0019] Figure 2 yes Figure 1 Top view of the structure.

[0020] In the figure: 1-high-speed railway pavement; 2-support; 3-high-speed railway pier; 4-ground; 5-cap beam; 6-capping platform; 7-capping platform pile foundation; 8-bored cast-in-place piles; 9-downline tunnel; 10-upline tunnel; 11-sleeve valve pipe grouting area; 12-TRD construction method wall; 13-sleeve valve pipe. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] See also Figure 1-2 , the utility model provides a technical solution:

[0023] Reference Figure 1 As shown, the angles between the up-line tunnel and the down-line tunnel and the high-speed railway line are 70° and 68° respectively, the buried depths of the tunnel tops are 13.89m and 14.63m respectively, and the minimum horizontal distance between the outer contour of the tunnel and the center of the pile foundation is 7.90m.

[0024] The isolation reinforcement structure passes through the soil layers in sequence: plain fill, silty clay, silty clay, medium-coarse sand, and medium-weathered muddy siltstone.

[0025] Furthermore, before TRD construction, axis measurement was carried out using a total station and theodolite to control the verticality of the pile driver column guide frame and the wall position deviation, which were kept within L / 250 and 0.05m respectively. These measures ensured the accuracy of construction and wall position, thereby improving the overall project quality and safety.

[0026] Furthermore, the next step is carried out only after the initial setting strength of the TRD method wall is reached to ensure that the construction sequence does not affect the stability and quality of the wall.

[0027] Furthermore, in order to avoid the collapse of the boreholes near the bridge piles, a steel sleeve wall protection drilling technology was specially designed. The construction was carried out using a fully rotary drilling rig and the sleeve was not removed, so as to minimize the impact of the construction on the high-speed railway bridge piles.

[0028] Furthermore, reasonable drilling process, hole cleaning, lowering of steel cage and pouring of concrete are adopted to ensure that the steel sleeve enters the hole first and then drilling is carried out to ensure the quality and stability of pile foundation construction.

[0029] Furthermore, during the installation process, the steel cage must be kept vertical to avoid bending and deformation, and ensure that the thickness of the protective layer and the elevation of the cage bottom meet the requirements. After the steel cage is in place, the elevation error of the top and bottom surfaces should be controlled to no more than 10mm.

[0030] Furthermore, in order to reduce the impact of bored piles on high-speed railway bridge piles, it is planned to carry out drilling and pouring in stages. After each batch of bored piles is poured, the next batch of construction can be carried out. A symmetrical drilling method is adopted, that is, drilling and pouring of the same construction batch is carried out on both sides of the pier foundation at the same time.

[0031] The construction of bored cast-in-place piles adopts the steel sleeve wall rotary drilling technology. The steel sleeve adopts welded round steel pipe D1100x16mm, the material is Q235B, the top surface is 30cm higher than the ground, the steel sleeve follows the whole pile and the central vertical line coincides with the center line of the pile. The allowable plane error is ±50mm, and the vertical inclination does not exceed 1%. During the drilling process, it is necessary to regularly check the displacement and sinking of the casing and make timely adjustments; a 1m×0.8m crown beam is set on the top of the bored cast-in-place pile.

[0032] Furthermore, the reinforcement areas between the bored piles are reinforced by grouting with sleeve valve pipes with a spacing of 1.2m×1.2m. The sleeve valve pipes are all made of 42.5 grade ordinary Portland cement, the verticality deviation of the grouting holes is ≤1%, the PH of the water for grouting is ≥4, and the flow rate is (7-10)L / min; the ambient temperature and humidity during the grouting process are strictly controlled to ensure that the slurry works under the best curing conditions; for extreme weather conditions, a heating or cooling system is used to ensure that the slurry is not affected by temperature; skip hole interval grouting is used, and when dealing with a large groundwater flow rate, grouting should be started from the high head side, for soil layers with the same seepage coefficient, the cap is first capped and then grouting is performed from the bottom to the top, and for soil layers whose permeability coefficient increases with depth, grouting is performed from the bottom to the top.

[0033] During the shield tunneling period, the operating speed of the high-speed rail is limited to 160km / h. During construction, special attention should be paid to the safety protection of high-speed rail piers, beams and other railway facilities.

[0034] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum with close side penetration of a high-speed railway bridge pile, characterized by: It includes bored piles (8), sleeve valve pipe grouting area (11) and TRD construction wall (12); The sleeve valve pipe grouting area (11) is formed by arranging sleeve valve pipes (13) between two rows of bored piles (8) at a row spacing and pipe spacing of 1.2m to 1.3m, and the reinforcement range is 3m above the shield tunnel vault to 2m below the tunnel floor.

2. According to claim 1, a comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum passing through a high-speed railway bridge pile at a close distance is characterized by: The TRD construction wall (12) is arranged at a position 2 m along the outer contour of the tunnel and close to the outer side of the bored pile (8); The TRD construction method wall (12) vertically reaches 5m below the bottom plate of the shield tunnel to form a 0.6m thick water-stopping structure.

3. The comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum with close side penetration of a high-speed railway bridge pile according to claim 1, characterized in that: The bored cast-in-place piles (8) are distributed as isolation piles at a distance of 1 m from the outer contours of the up-line tunnel (10) and the down-line tunnel (9) on both sides, and extend about 9.5 m beyond the high-speed railway cap pile foundation (7) in the excavation direction.

4. The comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum with close side penetration of a high-speed railway bridge pile according to claim 3 is characterized by: The bored piles (8) vertically reach 5 m below the bottom plate of the shield tunnel.

5. The comprehensive isolation and reinforcement structure for a shield tunnel in a permeable soft stratum with close side penetration of a high-speed railway bridge pile according to claim 1, characterized in that: The sleeve valve pipe (13) is a combination of a 50×5 mm galvanized grouting inner pipe and a PVC grouting outer pipe, and the verticality deviation of the grouting hole is ≤1%.

Images