Soil hole excavation supporting system and construction method

Abstract

The invention provides a soil hole excavation supporting system and a construction method, the soil hole excavation supporting system comprises a pipe shed, a plurality of top arch drainage holes, a plurality of tunnel face drainage holes and a plurality of glass fiber anchor rods, a tunnel face concrete layer is sprayed on the surface of an upper half hole tunnel face, steel fiber concrete is sprayed on the wall of a soil hole, and a reinforcing mesh is hung on the wall of the soil hole; a plurality of top steel arches are arranged on the top arch of the upper half hole, a bottom steel arch is arranged on the bottom arch of the lower half hole, the top steel arches are fixedly connected with the bottom steel arches, re-spraying concrete is sprayed on the inner surfaces of the top steel arches and the inner surfaces of the bottom steel arches, and the top steel arches of adjacent footage are connected and fixed through angle steel and longitudinal connecting ribs. The tunnel face is supported through the glass fiber anchor rods, the advanced pipe shed and the gradually-changed top steel arch frame and bottom steel arch frame are adopted, structural stress is reasonable, the excavation footage speed is high, the defect that according to a traditional supporting method, construction steps are affected by multiple partition blocks or reserved core soil, and consequently consumed time is long is overcome, the construction period is obviously shortened, and the construction efficiency is improved. And the practicability of actual construction is high.

Description

Technical Field

[0001] The present invention relates to the technical field of soil cave excavation support, and particularly relates to a soil cave excavation support system and a construction method thereof. Background Art

[0002] In hydraulic structures, as an important water conveyance structure, a tunnel may encounter soil caves under poor geological conditions or limited layout. For those with shallow soil cover, large-scale open excavation can be directly considered. For those with deep soil cover, it is difficult to carry out open excavation. In this case, strong support is usually required. Conventional construction methods include leaving a core soil, bench method, cross middle diaphragm method, double side drift method, etc. Among them, the method of leaving a core soil lacks theoretical demonstration and support, and this commonly used design is not recognized in overseas projects. Other methods generally take a long time, prolong the construction period, have low construction efficiency, and lack support design and methods for large-section soil caves rich in water and soil. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a soil cave excavation support system, which can solve the problems of long construction time in traditional soil cave excavation and lack of support design for large-section soil caves rich in water and soil.

[0004] To this end, the present invention adopts the following technical solutions: A soil cave excavation support system includes pipe roofs driven in the upper half of the tunnel crown and a number of crown drainage holes. A number of face drainage holes and a number of glass fiber bolts are arranged along the excavation direction of the upper half of the tunnel face. A face concrete layer is sprayed on the surface of the upper half of the tunnel face. A number of lower drainage holes are arranged below the upper half of the tunnel face. Vertical drainage holes are vertically driven in the lower half of the tunnel. Steel fiber concrete is sprayed on the soil cave wall and a steel mesh is hung. A number of top steel arch frames are arranged on the upper half of the tunnel crown, and a bottom steel arch frame is arranged on the bottom arch of the lower half of the tunnel. The top steel arch frame and the bottom steel arch frame are fixedly connected. Temporary inverted arches are respectively fixed to the lower parts of the top steel arch frames. The temporary inverted arches are located between the top steel arch frames and the bottom steel arch frames. The outer surfaces of the top steel arch frames and the bottom steel arch frames are closely attached to the steel mesh. Sprayed concrete is sprayed on the inner surfaces of the top steel arch frames and the bottom steel arch frames. The adjacent top steel arch frames are connected and fixed by angle steels and longitudinal connecting bars.

[0005] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions, or use a combination of these further technical solutions: The crown drainage holes are connected to drainage hoses. One end of the drainage hoses is led out of the tunnel or led to a temporary sump. A water pump is arranged in the vertical drainage hole and is connected to a lead pipe to lead out of the tunnel or to the temporary sump.

[0006] A first support steel plate is fixed to the lower end of the top steel arch frame. A middle section reinforcement plate is provided between the top steel arch frame and the support steel plate. A steel plate foundation is provided below the support steel plate. A number of reinforcement bars are fixed between the steel plate foundation and the support steel plate. A second support steel plate is fixed to the upper end of the bottom steel arch frame. The second support steel plate is closely attached to the steel plate foundation. The first support steel plate, the steel plate foundation and the second support steel plate are fixedly connected by steel arch frame connection bolts.

[0007] Reinforcement triangular plates are respectively fixed to both sides of the web of the lower part of the top steel arch frame. A second connection steel plate is fixed to the inner side of the reinforcement triangular plate. A first connection steel plate is fixed to the inner side of the second connection steel plate. A load-bearing steel plate is fixed to the inner side of the first connection steel plate. The end of the load-bearing steel plate is connected to the temporary inverted arch by temporary bolts.

[0008] The driving range of the pipe shed is 120° of the top arch of the upper half of the tunnel, and the outward expansion angle of the pipe shed is 5°.

[0009] The upper surface of the top steel arch frame with the same footage is arranged close to the slope of the pipe shed.

[0010] The purpose of the present invention also lies in overcoming the deficiencies of the above-mentioned prior art and providing a construction method for a soil cave excavation support system, which can solve the problems of long construction time in traditional soil cave excavation and lack of support design for large-section soil caves rich in water and soil.

[0011] To this end, the present invention adopts the following technical solutions: A support method for a soil cave excavation support system includes the following steps: a. First, drive a pipe shed with an outward expansion angle of 5° within the range of 120° of the top arch of the upper half of the soil cave; b. Excavate the upper half of the tunnel, initially spray a shotcrete layer on the face of the upper half of the tunnel, then drive glass fiber bolts, drill top arch drainage holes for the top arch, and use drainage hoses to lead the water out of the tunnel or into a temporary sump; c. Drill face drainage holes on the face. The face drainage holes will be continuously excavated during the advancing process. In addition, drill partial drainage holes near the lower part of the face; d. Use a suitable excavation machine to excavate the upper half of the tunnel along the face and the excavation line of the upper half of the tunnel. Adopt short footage and top arch grooved excavation. Immediately after excavation, initially spray steel fiber concrete on the top arch and the temporary inverted arch areas of the tunnel body to seal the exposed soil mass; e. Hang wire mesh, erect the top steel arch frame and the bottom temporary inverted arch, ensure that the top steel arch frame is closely attached to the pipe shed, and connect the adjacent top steel arch frames with angle steel and longitudinal connecting bars to form an integral body; f. On both sides of the lower web of the top steel arch, reinforcing triangular plates are welded respectively. On the inner side of the reinforcing triangular plates, second connecting steel plates are welded. On the inner side of the second connecting steel plates, first connecting steel plates are fixed by steel plate bolts. On the inner side of the first connecting steel plates, load-bearing steel plates are welded. The end of the load-bearing steel plate is connected to the temporary inverted arch through temporary bolts. At the bottom of the upper half-hole steel arch, support steel plates, reinforcing steel bars and steel plate foundations are welded. The steel plate foundations are seated on the soil base with sprayed steel fiber concrete; g. Spray and re-spray concrete on the top steel arch to cover the top steel arch to form an integral force-bearing structure; h. Drill vertical drainage holes at certain intervals in the lower half-hole, install submersible pumps inside and connect the leading pipes to lead them out of the tunnel or to a temporary sump; i. After the upper half-hole advances an appropriate distance, excavate the lower half-hole. Remove the temporary bolts on the temporary inverted arch structure with short footage. After complete removal, connect the first support steel plate, the said steel plate foundation, and the second support steel plate between the top steel arch and the bottom steel arch by using the steel arch connecting bolts; j. After removing each section of the temporary inverted arch, use appropriate excavation machinery to excavate the lower half-hole. After reaching the permanent shape, initially spray steel fiber concrete. Immediately install the bottom steel arch after hanging the mesh, and firmly connect it to the top steel arch through the steel arch connecting bolts; k. Spray and re-spray concrete on the bottom steel arch to cover the bottom steel arch to form an integral force-bearing structure; l. Repeat the above steps and steadily advance the excavation.

[0012] Compared with the prior art, the present invention has the following advantages and beneficial effects: By adopting the vertical excavation of the working face in the upper half-hole combined with the systematic drainage structure, the excavation construction operation is effectively and orderly promoted. Among them, the working face is supported by glass fiber bolts, and advanced pipe roofs and top and bottom steel arches with a gradual change type are adopted. The structure has reasonable force, fast excavation footage speed, and avoids the disadvantage of long time consumption caused by the multi-block or reserved core soil in the traditional support method affecting the construction sequence, significantly shortening the construction period and having strong practicability in actual construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the longitudinal sectional view of the present invention.

[0014] Figure 2 is the present invention Figure 1 the A-A cross-sectional view in.

[0015] Figure 3 is the present invention Figure 1 the B-B cross-sectional view in.

[0016] Figure 4 is the schematic diagram of the typical connection structure of the top steel arch of the present invention.

[0017] Figure 5 For the present invention Figure 1 in detail Figure 1 .

[0018] Figure 6 For the present invention Figure 1 C-C cross-sectional view in the present invention

[0019] Figure 7 For the present invention Figure 6 in detail Figure 2 .

[0020] Figure 8 For the present invention Figure 7 a-a cross-sectional view in the present invention

[0021] Figure 9 For the present invention Figure 6 in detail Figure 3 .

[0022] Figure 10 For the present invention Figure 9 b-b cross-sectional view in the present invention Detailed implementation manner

[0023] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation manners of the present invention will be described below in conjunction with specific embodiments. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals represent the same or similar functional elements throughout. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation on the present invention; for better illustration of this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as a limitation on the present invention.

[0024] The present invention will be further described below in conjunction with the drawings and embodiments, but it is not used as a basis for limiting the present invention.

[0025] A soil cave excavation support system provided by the present invention includes a pipe shed 1 and a number of crown drainage holes 11 drilled in the upper half of the crown arch. A number of face drainage holes 9 and a number of glass fiber anchor bolts 10 are arranged along the excavation direction of the upper half face 8. A face concrete layer 6 is sprayed on the surface of the upper half face 8. A number of lower drainage holes 7 are arranged below the upper half face 8. Vertical drainage holes 5 are vertically drilled in the lower half cave. Steel fiber concrete 2 is sprayed on the soil cave wall and a steel mesh 31 is hung. A number of top steel arch frames 41 are arranged on the upper half crown arch, and a bottom steel arch frame 42 is arranged on the lower half invert arch. The top steel arch frame 41 and the bottom steel arch frame 42 are fixedly connected. Temporary inverted arches 15 are respectively fixed to the lower parts of the top steel arch frames 41. The temporary inverted arches 15 are located between the top steel arch frames 41 and the bottom steel arch frames 42. The outer surfaces of the top steel arch frames 41 and the bottom steel arch frames 42 are closely attached to the steel mesh 31. Resprayed concrete 32 is sprayed on the inner surfaces of the top steel arch frames 41 and the bottom steel arch frames 42. The adjacent top steel arch frames 41 of the same footage are connected and fixed by angle steel 17 and longitudinal connecting bars 20.

[0026] In this embodiment, the soil cave is divided into an upper half cave and a lower half cave, and stepped excavation is carried out respectively. The temporary inverted arch 15 is used to ensure the force, and the upper half face 8 is supported by combining the glass fiber anchor bolts 10.

[0027] The crown drainage holes 11 are connected to drainage hoses 12. One end of the drainage hose 12 is led out of the cave or led to a temporary sump. A water pump is arranged in the vertical drainage hole 5 and connected to a lead pipe to lead out of the cave or to a temporary sump.

[0028] A first support steel plate 25 is fixed to the lower end of the top steel arch frame 41. A middle section strengthening plate 18 is arranged between the top steel arch frame 41 and the support steel plate 25. A steel plate foundation 22 is arranged below the support steel plate 25. A number of strengthening steel bars 23 are fixed between the steel plate foundation 22 and the support steel plate 25. A second support steel plate 21 is fixed to the upper end of the bottom steel arch frame 42. The second support steel plate 21 is closely attached to the steel plate foundation 22. The first support steel plate 25, the steel plate foundation 22 and the second support steel plate 21 are fixedly connected by steel arch frame connecting bolts 24.

[0029] Reinforcing triangular plates 26 are respectively fixed to both sides of the web of the lower part of the top steel arch frame 41. A second connecting steel plate 30 is fixed to the inner side of the reinforcing triangular plate 26. A first connecting steel plate 29 is fixed to the inner side of the second connecting steel plate 30. A load-bearing steel plate 31 is fixed to the inner side of the first connecting steel plate 29. The end of the load-bearing steel plate 31 is connected to the temporary inverted arch 15 by a temporary bolt 27.

[0030] The driving range of the pipe shed 1 is 120° of the upper half crown arch, and the outward expansion angle of the pipe shed 1 is 5°.

[0031] The upper surfaces of the top steel arch frames 41 of the same footage are arranged close to the slope of the pipe shed 1.

[0032] A construction method of a soil cave excavation support system provided by the present invention includes the following steps: a. First, drive pipe shed 1 with an outward expansion angle of 5° within the range of 120° of the top arch of the upper half of the soil cave; b. Excavate the upper half of the cave, initially spray shotcrete layer 6 on the face 8 within the range of the upper half of the cave, then drive glass fiber anchor bolts 10, drive top arch drainage holes 11 in the top arch, and use drainage flexible hoses 12 to lead the water out of the cave or into a temporary sump; c. Drive face drainage holes 9 on the face. The face drainage holes 9 will be continuously excavated during the advancing process. In addition, drive part drainage holes 7 at the lower part of the face; d. Use a suitable excavation machine to excavate the upper half of the cave along the face and excavation line of the upper half of the cave. Adopt short footage and top arch grooved excavation. Immediately after excavation, initially spray steel fiber shotcrete 2 in the top arch and temporary invert areas of the tunnel body to seal the exposed soil mass; e. Hang wire mesh 31, erect top steel arch frame 41 and temporary invert 15 at the bottom, ensure that the top steel arch frame 41 is closely attached to the pipe shed 1, and connect adjacent top steel arch frames 41 with angle steel 17 and longitudinal connecting bars 20 to form an integral body; f. Weld reinforcing triangular plates 26 on both sides of the lower web of the top steel arch frame 41. Weld a second connecting steel plate 30 on the inner side of the reinforcing triangular plate 26. Fix the first connecting steel plate 29 on the inner side of the second connecting steel plate 30 with steel plate bolts 28. Weld a bearing steel plate 31 on the inner side of the first connecting steel plate 29. Connect the end of the bearing steel plate 31 to the temporary invert 15 through temporary bolts 27. Weld support steel plates 25, reinforcing bars 23 and steel plate foundations 22 at the bottom of the upper half of the steel arch frame 4. The steel plate foundation 22 is placed on the soil base where the steel fiber shotcrete 2 has been sprayed; g. Spray and re-spray shotcrete 32 on the top steel arch frame 41 to cover the top steel arch frame 41 to form an integral force; h. Drive vertical drainage holes 5 at a certain interval in the lower half of the cave, install a water pump inside and connect a lead pipe to lead the water out of the cave or to a temporary sump; i. After the upper half of the cave advances an appropriate distance, excavate the lower half of the cave. Remove the temporary bolts 27 on the temporary invert structure 15 with short footage. After complete removal, connect the first support steel plate 25, steel plate foundation 22 and second support steel plate 21 between the top steel arch frame 41 and the bottom steel arch frame 42 with steel arch frame connecting bolts 24; j. After removing 1 - 3 frames of the temporary invert 15 each time, use a suitable excavation machine to excavate the lower half of the cave. After excavating to the permanent shape, initially spray steel fiber shotcrete 2. Immediately after hanging the mesh, install the bottom steel arch frame 42 and firmly connect it to the top steel arch frame 41 through steel arch frame connecting bolts 24; k. Spray shotcrete 3 on the bottom steel arch 42 to cover the bottom steel arch 42 to form an integral force-bearing structure. l. Repeat the above steps and steadily advance the excavation.

[0033] Based on the description and drawings of the present invention, those skilled in the art can easily manufacture or use a soil cave excavation support system and construction method of the present invention, and can achieve the positive effects recorded in the present invention.

[0034] It should be noted that the terms "including" and "having" and any variations thereof in the description, claims and drawings of the present invention are intended to cover non-exclusive inclusion. The terms "installed", "set", "provided with", "connected", "connected to", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two mechanisms, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "one end", "the other end", "outer side", "inner side", "horizontal", "end", "length", "outer end", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated mechanism or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. The terms "first" and "second" are also used only for simplicity in description and do not indicate or imply relative importance.

[0036] In addition, when practicing the claims of the present invention, those skilled in the art can understand and influence the changes to the disclosed embodiments through the study of the drawings, the disclosure and the appended claims. In addition, in the claims and the description, words such as "including" and "containing" do not exclude other elements or steps, and non-plural nouns do not exclude their plural forms.

[0037] The above are only the preferred embodiments of the present invention, and are not used to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made in accordance with the present invention are covered by the scope of the claims of the present invention, and no further examples will be given here.

Claims

1. An earth cave excavation support system, characterized in that, It includes pipe sheds (1) driven in the upper half of the crown arch and several crown arch drainage holes (11). Along the excavation direction of the heading face (8) of the upper half of the tunnel, several heading face drainage holes (9) and several fiberglass bolts (10) are arranged. A heading face concrete layer (6) is sprayed on the surface of the heading face (8) of the upper half of the tunnel. Several lower drainage holes (7) are arranged below the heading face (8) of the upper half of the tunnel. Vertical drainage holes (5) are vertically driven in the lower half of the tunnel. Steel fiber concrete (2) is sprayed on the earthen tunnel wall and a steel mesh (31) is hung. Several top steel arch frames (41) are arranged on the crown arch of the upper half of the tunnel. A bottom steel arch frame (42) is arranged on the invert arch of the lower half of the tunnel. The top steel arch frame (41) and the bottom steel arch frame (42) are fixedly connected. Temporary inverted arches (15) are respectively fixed to the lower parts of the top steel arch frames (41). The temporary inverted arches (15) are located between the top steel arch frames (41) and the bottom steel arch frames (42). The outer surfaces of the top steel arch frames (41) and the bottom steel arch frames (42) are closely attached to the steel mesh (31). Shotcrete (32) is sprayed on the inner surfaces of the top steel arch frames (41) and the bottom steel arch frames (42). The adjacent top steel arch frames (41) of the same footage are connected and fixed by angle steels (17) and longitudinal connecting bars (20).

2. The soil cave excavation support system according to claim 1, characterized in that The crown arch drainage holes (11) are connected to drainage hoses (12). One end of the drainage hoses (12) is led out of the tunnel or led to a temporary sump. A water pump is arranged in the vertical drainage hole (5) and is connected to a leading pipe to lead out of the tunnel or to a temporary sump.

3. The soil cave excavation and support system according to claim 1, characterized in that, A first support steel plate (25) is fixed to the lower end of the top steel arch frame (41). A middle section reinforcement plate (18) is arranged between the top steel arch frame (41) and the support steel plate (25). A steel plate foundation (22) is arranged below the support steel plate (25). Several reinforcing bars (23) are fixed between the steel plate foundation (22) and the support steel plate (25). A second support steel plate (21) is fixed to the upper end of the bottom steel arch frame (42). The second support steel plate (21) is closely attached to the steel plate foundation (22). The first support steel plate (25), the steel plate foundation (22) and the second support steel plate (21) are fixedly connected by steel arch frame connecting bolts (24).

4. A soil cave excavation support system as claimed in claim 1, wherein Reinforcing triangular plates (26) are respectively fixed to both sides of the web of the lower part of the top steel arch frame (41). A second connecting steel plate (30) is fixed to the inner side of the reinforcing triangular plate (26). A first connecting steel plate (29) is fixed to the inner side of the second connecting steel plate (30). A load-bearing steel plate (31) is fixed to the inner side of the first connecting steel plate (29). The end of the load-bearing steel plate (31) is connected to the temporary inverted arch (15) by a temporary bolt (27).

5. The soil cave excavation support system according to claim 1, characterized in that, The driving range of the pipe shed (1) is 120° of the crown arch of the upper half of the tunnel, and the outward expansion angle of the pipe shed (1) is 5°.

6. The soil cave excavation support system according to claim 1, characterized in that, The upper surfaces of the top steel arch frames (41) of the same footage are arranged close to the slope of the pipe shed (1).

7. The construction method of a soil cave excavation support system according to claim 1, characterized in that, It includes the following steps: a. First, install pipe shed (1) with an outward expansion angle of 5° within the range of 120° of the upper half of the top arch of the soil cave; b. Excavate the upper half of the cave. Initially spray the face concrete layer (6) on the face (8) within the range of the upper half of the cave, then install glass fiber bolts (10), drill top arch drainage holes (11) for the top arch, and use drainage hoses (12) to drain water out of the cave or into a temporary sump; c. Drill face drainage holes (9) on the face. The face drainage holes (9) will be continuously excavated during the advancement process. Additionally, drill partial drainage holes (7) at the lower part of the face; d. Use appropriate excavation machinery to excavate the upper half of the cave along the face and excavation line of the upper half of the cave. Adopt short footage and top arch grooved excavation. Immediately after excavation, initially spray steel fiber concrete (2) in the areas of the top arch of the cave body and the temporary inverted arch, and seal the exposed soil mass; e. Hang wire mesh sheets (31), erect top steel arch frames (41) and the bottom temporary inverted arch (15), ensuring that the top steel arch frames (41) are closely fitted with the pipe shed (1). Connect adjacent top steel arch frames (41) with angle steels (17) and longitudinal connecting bars (20) to form an integral whole; f. Weld strengthening triangular plates (26) on both sides of the lower webs of the top steel arch frames (41). Weld second connecting steel plates (30) on the inner sides of the strengthening triangular plates (26). Fix the first connecting steel plate (29) on the inner side of the second connecting steel plate (30) with steel plate bolts (28). Weld bearing steel plates (31) on the inner side of the first connecting steel plate (29). Connect the ends of the bearing steel plates (31) to the temporary inverted arch (15) through temporary bolts (27). Weld support steel plates (25), strengthening steel bars (23) and steel plate foundations (22) at the bottoms of the upper half cave steel arch frames (4). The steel plate foundations (22) are seated on the soil base where the steel fiber concrete (2) has been sprayed; g. Spray and re-spray concrete (32) on the top steel arch frames (41) to cover the top steel arch frames (41) to form an integral force-bearing structure; h. Drill vertical drainage holes (5) at certain intervals in the lower half of the cave, install submersible pumps inside and connect the leading pipes to drain water out of the cave or lead it to a temporary sump; i. After the upper half of the cave has advanced an appropriate distance, excavate the lower half of the cave. Remove the temporary bolts (27) on the temporary inverted arch structure (15) with short footage. After complete removal, connect the first support steel plates (25), the steel plate foundations (22), and the second support steel plates (21) between the top steel arch frames (41) and the bottom steel arch frames (42) with steel arch frame connecting bolts (24); j. After removing 1 - 3 frames of the temporary inverted arch (15) each time, use appropriate excavation machinery to excavate the lower half of the cave. After reaching the permanent shape, initially spray steel fiber concrete (2). Immediately after hanging the mesh, install the bottom steel arch frames (42) and firmly connect them to the top steel arch frames (41) with steel arch frame connecting bolts (24); k. Spray and re-spray concrete (3) on the bottom steel arch frames (42) to cover the bottom steel arch frames (42) to form an integral force-bearing structure; l. Repeat the above steps and steadily advance the excavation.

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