A prestressed anchor cable for slope support in karst areas

Abstract

The utility model relates to the technical field of prestressed anchor cables, and specifically, to a prestressed anchor cable used for supporting slopes in karst areas. It comprises a retaining structure, and an enlarged head type prestressed anchor cable structure is arranged between the retaining structure and the slope; after the borehole is continuously drilled and passes through part of the karst caves until a stable rock layer area without karst caves within a certain range is found, an expansion section is constructed, and a water stop strip is wrapped around the outer side of one end of the corrugated pipe and then inserted into the borehole, and the anchor cable body is connected to the bearing body and then penetrated into the expansion section from the corrugated pipe, and cement slurry is injected from the corrugated pipe until it is full, and the anchor cable body is locked in the borehole. The utility model has a simple structure and a reasonable construction, and can realize the construction of prestressed anchor cables in karst areas, does not require the prior treatment of karst caves, can provide effective pre-tightening force, and can provide a large anchoring force, so that the high slopes in the karst area can effectively control deformation after the prestressed anchor cables are applied, improve the overall stability of the slopes, do not waste cement slurry and fill karst caves, and are economical and applicable.

Description

Technical Field

[0001] The utility model relates to the technical field of prestressed anchor cables, in particular to a prestressed anchor cable used for slope support in karst areas. Background Art

[0002] Karst is a very uncommon unfavorable geological condition in my country, and construction activities in karst areas are also very common, and slope engineering in karst areas is one of them. In a high slope project in the karst area, pile-sheet wall + prestressed anchor cable is used for support. During the construction of the prestressed anchor cable, the cement slurry is never fully filled, resulting in the prestressed anchor cable not being able to play its role, endangering the safety and stability of the slope. Therefore, ordinary tension or pressure anchor cables are no longer applicable in karst areas. If the karst cave is treated in advance, the project cost may be greatly increased. The anchor cable structure in this technical solution came into being under this background, which can not only allow the anchor cable to play its pre-tightening function, but also does not need to treat the karst cave, and uses conventional processes, with low technical difficulty and convenient construction. Utility Model Content

[0003] The purpose of the utility model is to provide a prestressed anchor cable for slope support in karst areas. When constructing prestressed anchor cables in karst areas, there is no need to pre-treat caves, which greatly increases engineering costs, and the anchor cables can successfully play their pre-tightening role. At the same time, the construction difficulty is low, the technical difficulty is small, and the work efficiency is improved to solve the problems raised in the above-mentioned background technology.

[0004] In order to solve the above technical problems, the purpose of the utility model is to provide a prestressed anchor cable for slope support in karst areas, including a precast retaining structure, wherein an enlarged head prestressed anchor cable structure composed of a drill hole, a hole expansion section, a corrugated pipe, an anchor cable body, a mini steel cage, a bearing body, cement slurry, a water stop strip and a sealing anchor is arranged between the retaining structure and the slope; wherein:

[0005] The borehole is continuously drilled from the retaining structure toward the slope and passes through some caves until a stable rock formation area without caves within a certain range is found, and then an expansion section connected to the borehole is obtained through construction. The water stop strip is wrapped around the outer side of one end of the corrugated pipe and inserted into the borehole. After the anchor cable body is effectively connected to the bearing body, it is passed through the corrugated pipe until the bearing body is placed in the expansion section. A mini steel cage is welded on one side of the bearing body. The cement slurry is injected from the corrugated pipe until the expansion section is filled and flows back into the corrugated pipe and the borehole. The water stop strip contacts the cement slurry and absorbs water to block the borehole, and the sealing anchor locks the anchor cable body after stress is applied at the hole mouth end of the borehole.

[0006] As a further improvement of the technical solution, the retaining structure is a rigid retaining structure, or a reinforced concrete pile, or a reinforced concrete rib column, and the retaining structure and the prestressed anchor cable structure together constitute a slope retaining system.

[0007] As a further improvement of the present technical solution, the drilling is completed by means of an anchor drilling rig, the drilling angle is greater than or equal to 15°, and can be adjusted according to the drilling results; the expansion section is located in a stable rock formation area within a certain range without the cave area, and the expansion section is completed by mechanical expansion.

[0008] As a further improvement of the technical solution, the bellows is made of PE material, and the outer surface of the bellows is sprayed with an injection molding layer and an anti-rust layer.

[0009] As a further improvement of the technical solution, the anchor cable body is a steel strand, the cross-sectional diameter of each bundle of the anchor cable body is 15.2 mm or 17.2 mm, and the cable body of the anchor cable body is painted with red paint for corrosion protection and wrapped with a plastic film.

[0010] As a further improvement of the technical solution, the carrier is a circular steel plate, and a plurality of holes are reserved on the steel plate of the carrier;

[0011] The anchor cable body passes through the reserved hole of the carrier body and is tightly connected with the carrier body through an extrusion sleeve and its matching tie rod bolts.

[0012] As a further improvement of the technical solution, the main reinforcement of the mini steel cage is made of HRB400 steel bars with a diameter of 10 mm, and the stirrups of the mini steel cage are cold-rolled steel wire spiral stirrups;

[0013] The mini steel cage is connected to the carrier by welding, and the main bars of the mini steel cage are welded to the steel plate surface of the carrier.

[0014] As a further improvement of the technical solution, the water-cement ratio of the cement slurry is 0.38-0.5.

[0015] As a further improvement of the present technical solution, the waterstop strip is a water-swelling waterstop strip, which is wrapped around the outer wall of one end of the corrugated pipe and fixed with a steel wire, and the number of layers of the waterstop strip wrapped is greater than or equal to three.

[0016] As a further improvement of the technical solution, the anchor is a cast-in-place concrete structure, the concrete grade of the anchor is C30, and the anchor is in the shape of a square pyramid;

[0017] After the curing period of the cement slurry expires, prestress is applied to the anchor cable body and locked to the retaining structure, and the exposed end of the anchor cable body outside the borehole is sealed with the sealing anchor.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] 1. This is applied to the prestressed anchor cables for slope support in karst areas. It has simple structure, reasonable construction, strong applicability, convenient construction, mature technology, common materials, low technical difficulty and convenient construction. It can realize the construction of prestressed anchor cables in karst areas, so that the high slopes in karst areas can effectively control deformation after the prestressed anchor cables are applied, improve the overall stability of the slopes, and do not waste cement slurry and fill caves. It is economical and applicable;

[0020] 2. This application is used in prestressed anchor cables for slope support in karst areas. By constructing prestressed enlarged head anchor cables in a rock layer area without caves within a certain range, there is no need to deal with caves in advance. It can provide effective pre-tightening force and greater anchoring force to control the deformation of the support system and protect the stability of the entire slope. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0022] Figure 2 It is a structural schematic diagram of the carrier in the utility model;

[0023] Figure 3 For this utility model Figure 2 Schematic diagram of the structure of the NN section.

[0024] In the figure:

[0025] 1. Retaining structure; 2. Drilling hole; 3. Hole expansion section; 4. Corrugated pipe; 5. Anchor cable body; 6. Mini steel cage; 7. Bearing body; 71. Extrusion sleeve; 72. Tie bolt; 8. Cement slurry; 81. Primary grouting pipe; 82. Secondary grouting pipe; 9. Water stop strip; 10. Anchor seal; A. Top of slope; B. Top of slope; C. Cave. DETAILED DESCRIPTION

[0026] 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.

[0027] Example 1

[0028] like Figure 1-Figure 3As shown, this embodiment provides a prestressed anchor cable for slope support in karst areas, including a precast support structure 1, the top of which is flush with the top A of the slope, and the bottom of which passes through the bottom B of the slope and extends to be inserted into the underground of the slope;

[0029] An enlarged head type prestressed anchor cable structure composed of a borehole 2, an expanded hole section 3, a corrugated pipe 4, an anchor cable body 5, a mini steel cage 6, a bearing body 7, cement slurry 8, a water stop strip 9 and a sealing anchor 10 is arranged between the retaining structure 1 and the slope; wherein:

[0030] After the borehole 2 is continuously drilled from the retaining structure 1 toward the slope and passes through part of the cave C until a stable rock formation area without caves within a certain range is found, an expansion section 3 connected to the borehole 2 is obtained through construction, a water stop strip 9 is wrapped around the outer side of one end of the corrugated pipe 4 and inserted into the borehole 2, and the anchor cable body 5 is effectively connected to the bearing body 7 and then penetrated from the corrugated pipe 4 until the bearing body 7 is placed in the expansion section 3, a mini steel cage 6 is welded on one side of the bearing body 7, and cement slurry 8 is injected from the corrugated pipe 4 until the expansion section 3 is filled and reversely flows into the corrugated pipe 4 and the borehole 2 until it is reversed from the pipe mouth of the corrugated pipe 4, and the grouting is stopped; the water stop strip 9 can block the borehole 2 after absorbing water in contact with the cement slurry 8, and the sealing anchor 10 locks the anchor cable body 5 after stress is applied at the hole end of the borehole 2 to complete the retaining system.

[0031] In this embodiment, the retaining structure 1 is a rigid retaining structure, or a reinforced concrete pile, or a reinforced concrete rib column. The retaining structure 1 and the prestressed anchor cable structure together constitute a slope retaining system.

[0032] In this embodiment, the borehole 2 is completed by an anchor drilling rig, the drilling angle is not less than 15°, and can be adjusted according to the drilling results. The diameter of the borehole 2 is preferably 150 mm; the expansion section 3 is located in a stable rock formation area within a certain range of the cave-free zone C, and the expansion section 3 is completed by mechanical expansion. The diameter of the expansion section 3 is preferably 300 mm and the length is at least 2 m.

[0033] In this embodiment, the bellows 4 is made of PE material, the diameter of the bellows 4 is preferably 130 mm, and the outer surface of the bellows 4 is sprayed with an injection molding layer and an anti-rust layer.

[0034] In this embodiment, the anchor cable body 5 is a steel strand, and the cross-sectional diameter of each bundle of the anchor cable body 5 is 15.2 mm or 17.2 mm. The anchor cable body 5 is painted with red paint for corrosion prevention and wrapped with a plastic film.

[0035] In this embodiment, the carrier 7 is a circular steel plate, preferably with a diameter of 200 mm and a thickness of 30 mm, and a plurality of holes are reserved on the steel plate of the carrier 7;

[0036] The anchor cable body 5 passes through the reserved hole of the carrier 7 and is tightly connected to the carrier 7 through the extrusion sleeve 71 and its matching pull rod bolt 72.

[0037] Further, the diameter of the mini steel cage 6 is preferably 180 mm, the length is 800 mm, the main bars of the mini steel cage 6 are preferably eight in total, HRB400 steel bars with a diameter of 10 mm are used, and the stirrups of the mini steel cage 6 are cold-rolled steel wire spiral hoops, preferably with a diameter of 6.5 mm and a spacing of 150 mm;

[0038] The mini steel cage 6 is welded to the carrier 7 , and the main bars of the mini steel cage 6 are welded to the steel plate surface of the carrier 7 .

[0039] In this embodiment, the water-cement ratio of the cement slurry 8 is 0.38-0.5.

[0040] In this embodiment, the waterstop strip 9 is a water-swelling waterstop strip, which is wrapped around the outer wall of one end of the corrugated tube 4 and fixed with a steel wire. The number of layers of the waterstop strip 9 is not less than three, and the winding length is preferably 1000 mm.

[0041] In this embodiment, the anchor 10 is a cast-in-place concrete structure, the concrete grade of the anchor 10 is C30, and the anchor 10 is in the shape of a square pyramid, preferably with an upper surface size of 150mm*150mm, a lower surface size of 250mm*250mm, and a height of 200mm;

[0042] After the curing period of the cement slurry 8 expires, prestress is applied to the anchor cable body 5 and locked to the retaining structure 1 , and the exposed end of the anchor cable body 5 outside the borehole 2 is sealed with a sealing anchor 10 .

[0043] In summary, the utility model has a simple structure, reasonable construction, mature technology, common materials, low technical difficulty and convenient construction; by constructing prestressed enlarged head anchor cables in rock formations without caves within a certain range, there is no need to process the caves in advance, and effective pre-tightening force can be provided. It can provide a large anchoring force to control the deformation of the retaining system and thus protect the stability of the entire slope.

[0044] The use steps of the utility model for the prestressed anchor cable for slope support in karst areas include:

[0045] S1. Before use, the location and distribution of soil caves or karst caves in the rock formation area must be explored, and a rock formation area without karst caves within a certain range must be found, and there must be no soil caves within a range of at least 10 square meters in the stable area;

[0046] S2. The designer needs to calculate and determine the tensile strength that the prestressed anchor cable needs to provide based on the degree of hazard of the slope, geological conditions, distribution of karst caves, etc., and then determine the number of anchor cable bodies 5, the position and length of the expansion section 3, the diameter and angle of the borehole 2 and other construction parameters;

[0047] S3. According to the above requirements, the prestressed anchor cable is constructed. After the drilling hole 2 is constructed to a rock layer area without caves within a certain range, the hole expansion section is constructed, and the anchor cable body 5 is manufactured at the same time.

[0048] S4, calculating the cutting length of the corrugated tube 4 according to the depth of the borehole 2, and placing the corrugated tube 4 into the borehole 2;

[0049] S5, put the prepared prestressed anchor cable body 5 and the connected bearing body 7 into the corrugated tube 4, with the bearing body 7 facing the direction of the borehole 2, and leaving a 500mm sediment section;

[0050] S6, grouting is performed at a relatively low pressure into the bellows 4 and the expansion section 3 through the primary grouting pipe 81, and the grouting is continued from bottom to top until the cement slurry 8 is returned from the pipe mouth of the bellows 4, and then the grouting is stopped; after the cement slurry 8 is initially set, secondary high-pressure grouting is performed through the secondary grouting pipe 82, and the grouting pressure is not less than 2.0 MPa;

[0051] S7, after the cement slurry 8 reaches the strength after the curing period, the prestressed anchor cable body 5 is applied with prestress and locked;

[0052] S8, construction sealing anchor 10, construction is completed.

[0053] A person of ordinary skill in the art can understand that the process of implementing all or part of the steps of the above-mentioned embodiments can be completed by hardware, or can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the above-mentioned storage medium can be a read-only memory, a disk or an optical disk, etc.

[0054] 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 prestressed anchor cable for slope support in karst areas, comprising a precast support structure (1), characterized in that: An enlarged head type prestressed anchor cable structure is arranged between the retaining structure (1) and the slope, and is composed of a drill hole (2), an expanded hole section (3), a corrugated pipe (4), an anchor cable body (5), a mini steel cage (6), a bearing body (7), cement slurry (8), a water stop strip (9) and a sealing anchor (10); wherein: The borehole (2) is continuously drilled from the retaining structure (1) toward the slope and passes through a portion of the karst cave (C) until a stable rock layer area without karst caves within a certain range is found. Then, an expansion section (3) connected to the borehole (2) is obtained through construction. The water stop strip (9) is wrapped around the outer side of one end of the corrugated pipe (4) and inserted into the borehole (2). After the anchor cable body (5) is effectively connected to the carrier (7), it is inserted into the corrugated pipe (4) until the carrier (7) is inserted. 7) is placed in the expansion section (3), a mini steel cage (6) is welded on one side of the carrier (7), the cement slurry (8) is injected from the corrugated pipe (4) until it fills the expansion section (3) and flows back into the corrugated pipe (4) and the borehole (2), the water stop strip (9) can block the borehole (2) after contacting with the cement slurry (8) and absorbing water, and the sealing anchor (10) locks the anchor cable body (5) after stress is applied at the hole end of the borehole (2).

2. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The retaining structure (1) is a rigid retaining structure, and the retaining structure (1) and the prestressed anchor cable structure together form a slope retaining system.

3. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The drilling hole (2) is completed by an anchor drilling rig, and the drilling angle is greater than or equal to 15°, and can be adjusted according to the drilling results; the expansion section (3) is located in a stable rock formation area within a certain range without the cave (C), and the expansion section (3) is completed by mechanical expansion.

4. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The bellows (4) is made of PE material, and the outer surface of the bellows (4) is sprayed with an injection molding layer and an anti-rust layer.

5. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The anchor cable body (5) is a steel strand, and the cross-sectional diameter of each cable bundle of the anchor cable body (5) is 15.2 mm or 17.2 mm. The cable body of the anchor cable body (5) is painted with red paint for corrosion prevention and wrapped with a plastic film.

6. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The carrier (7) is a circular steel plate, and a plurality of holes are reserved on the steel plate of the carrier (7); The anchor cable body (5) passes through a reserved hole of the carrier (7) and is tightly connected to the carrier (7) through an extrusion sleeve (71) and its matching pull rod bolt (72).

7. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The main reinforcement of the mini steel cage (6) is made of HRB400 steel bars with a diameter of 10 mm, and the stirrups of the mini steel cage (6) are cold-rolled steel wire spiral stirrups; The mini steel cage (6) is connected to the carrier (7) by welding, and the main reinforcement of the mini steel cage (6) is welded to the steel plate surface of the carrier (7).

8. The prestressed anchor cable for slope support in karst areas according to claim 1 is characterized in that: The water-cement ratio of the cement slurry (8) is 0.38-0.

5.

9. The prestressed anchor cable for slope support in karst areas according to claim 1, characterized in that: The water stop strip (9) is a water stop strip that expands when in contact with water. The water stop strip (9) is wound around the outer wall of one end of the corrugated tube (4) and fixed with a steel wire. The number of layers of the water stop strip (9) wound is greater than or equal to three.

10. The prestressed anchor cable for slope support in karst areas according to claim 1, characterized in that: The sealing anchor (10) is a cast-in-place concrete structure, the concrete grade of the sealing anchor (10) is C30, and the sealing anchor (10) is in the shape of a square pyramid; After the curing period of the cement slurry (8) expires, prestress is applied to the anchor cable body (5) and locked to the retaining structure (1), and the exposed end of the anchor cable body (5) outside the borehole (2) is sealed with the sealing anchor (10).

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