Variable-diameter reinforcement cage jet grouting anchor cable structure and construction method thereof

Abstract

The variable-diameter reinforcement cage rotary jet grouting anchor cable structure comprises a steel structure and cement soil in an anchor cable hole, and the anchor cable hole is formed through rotary jet grouting; the steel structure comprises an anchor cable set and a variable-diameter reinforcement cage, and the variable-diameter reinforcement cage is located in the expanded head portion of an anchor cable hole. The variable-diameter reinforcement cage comprises a lower anchoring part, an upper anchoring part and a vertical rib group; vertical ribs in the vertical rib group are hinged to the upper anchoring part and the lower anchoring part; the lower end of the rotary jet grouting drill rod is a hole shrinkage section and provided with a step face, the rotary jet grouting drill rod can feed the steel structure into the anchor cable hole through the step face and open the variable-diameter reinforcement cage, and a grout spraying hole is formed in the lower end of the hole shrinkage section. The invention further discloses a construction method of the variable-diameter reinforcement cage rotary jet grouting anchor cable structure. Cement soil in the anchor cable hole is used for supporting the hole wall, collapse of the anchor cable hole is avoided, after the variable-diameter reinforcement cage is fed into the anchor cable hole, reaming is conducted, the expanded head is formed, the variable-diameter reinforcement cage is opened through the jet grouting drill rod, and the quality of the expanded head of the variable-diameter reinforcement cage is guaranteed.

Description

Technical Field

[0001] The invention relates to a variable diameter steel bar cage rotary sprayed anchor cable structure and a construction method thereof. Background Art

[0002] In order to improve the stability of the anchor cable in the foundation, it is usually necessary to set a variable diameter steel cage at the bottom of the anchor cable. The variable diameter steel cage needs to pass through the thinner anchor cable hole at the top to reach the bottom of the anchor cable hole and enter into the reserved enlarged head chamber, and then the variable diameter steel cage is changed from a contracted state to an open state, and then pure cement slurry or concrete is injected into the enlarged head chamber, so that the opened variable diameter steel cage and the concrete or pure cement slurry form a whole, that is, the variable diameter steel cage enlarged head, so as to improve the stability of the anchor cable in the foundation.

[0003] When constructing anchor holes, different construction methods are used according to different geological structures. For hard strata, dry holes are generally formed. For soft strata, it is difficult to form dry holes due to easy hole collapse, so wet hole formation with mud wall protection is generally used. Although dry holes are easy to install anchor cables, in actual construction, it is difficult to completely empty the enlarged head chamber due to the contact of the drill rod. More or less earth will remain in the enlarged head chamber, and when the anchor cable enters the anchor hole, the hole wall will collapse due to the contact of the variable diameter steel cage. When the existing variable diameter hoop reinforcement cage is opened, it relies on its own elastic mechanism to push the vertical bars of the variable diameter steel cage to move outward and reach its set position. When the earth remaining in the enlarged head chamber affects the movement of the vertical bars, the vertical bars cannot reach their set positions, making the variable diameter steel cage unable to be fully opened, affecting the strength of the enlarged head of the variable diameter steel cage.

[0004] When the wet drilling method is used, the silt in the anchor hole is difficult to remove completely, which also makes it impossible to fully open the variable diameter steel cage, and easily causes cement slurry to wrap the soil, making it impossible to form the desired enlarged head, resulting in a reduction in the bearing capacity of the enlarged head, making it difficult to control the construction quality. Summary of the invention

[0005] In order to solve the above problems, the present application firstly proposes a variable diameter steel cage rotary spray anchor cable structure, which comprises a steel structure inserted into an anchor cable hole and cement soil wrapped on the steel structure, and the anchor cable hole is formed by a rotary spraying process; the steel structure comprises an anchor cable group and a variable diameter steel cage, wherein the variable diameter steel cage is located in the enlarged head of the anchor cable hole; the variable diameter steel cage comprises a lower anchoring part, an upper anchoring part and a vertical reinforcement group, the anchor cable group comprises 2-10 anchor cables which are parallel to each other and extend along the axial direction of the anchor cable hole, one end of each anchor cable facing the same direction is formed as an anchoring end, and the other end away from the anchoring end is formed as a tensioning end, the 2-10 anchor cables are arranged at intervals around a central axis, the anchoring end of each anchor cable is fixed on the lower anchoring part, and each anchor cable freely passes through the upper anchoring part, and the upper anchoring part is located on the upper side of the lower anchoring part;

[0006] The vertical bar group includes a plurality of vertical bars arranged at intervals around the anchor cable group, and each vertical bar has an upper hinged bar and a lower hinged bar corresponding to each vertical bar, the two ends of the upper hinged bar are respectively hinged to the upper part and the upper anchoring part of the corresponding vertical bar, and the two ends of the lower hinged bar are respectively hinged to the lower part and the lower anchoring part of the corresponding vertical bar; pushing the upper anchoring part toward the lower anchoring part can make the vertical bar move from a contracted state to an open state;

[0007] The upper anchoring part is provided with an upper drill rod hole, and the lower anchoring part is provided with a lower drill rod hole, and the upper drill rod hole and the lower drill rod hole are coaxially arranged in the extending direction of the anchor hole; the lower end of the rod body of the rotary jet drill rod is radially reduced to form a reduced diameter section and a step surface facing the lower end surface of the rotary jet drill rod, and the reduced diameter section can pass through the upper drill rod hole and the lower drill rod hole in sequence, and the step surface is pressed against the upper side edge of the lower drill rod hole to send the steel structure into the anchor hole; after the steel structure is sent into the anchor hole, cement slurry is sprayed by the rotary jet drill rod to expand the hole to form an enlarged head cavity, and then the rotary jet drill rod is lifted upward, and the step surface is pressed against the upper side edge of the upper drill rod hole, and the upper anchoring part is pushed toward the lower anchoring part, so that the vertical reinforcement changes from a contracted state to an open state; the soft rope stirrup is wound around the vertical reinforcement group; at least a grouting hole is provided at the lower end of the reduced diameter section.

[0008] In the present application, the anchor hole is formed by a rotary jet process, and there is cement soil formed by a mixture of cement slurry and earth in the anchor hole. The supporting effect of the cement soil is used to avoid the collapse of the anchor hole. The steel structure is sent into the anchor hole by using the step surface on the rotary jet drill rod, and then the rotary jet drill rod is used to expand the hole. Finally, the step surface is used to push the upper anchoring part downward, and the vertical reinforcement is pushed to reach an open state. Since the present application can effectively avoid the collapse of the anchor hole, and the earth in the anchor hole is mixed in the cement slurry and forms cement soil together with the cement slurry, there are no independent soil blocks or silt blocks, and the formation of cement slurry wrapped in soil is avoided. The present application utilizes the fluidity of cement soil to smoothly deliver the variable diameter steel bar cage to its set position. After the formation of the enlarged head cavity is completed, the upper anchoring part is pushed by the rotary jet drill rod to move the vertical bars outward. Since the moving distance of the rotary jet drill rod can be intuitively confirmed, the moving distance of the vertical bars can be guaranteed, and the vertical bars can reach their set positions, thereby ensuring the quality of the enlarged head of the variable diameter steel bar cage.

[0009] Specifically, the upper anchoring portion includes an upper pressure plate and an upper hinge ring formed on the lower side of the upper pressure plate, the outer diameter of the upper hinge ring is smaller than the outer diameter of the upper pressure plate, and the upper hinge rib is hinged on the upper hinge ring;

[0010] The lower anchoring part includes a lower pressure plate and a lower hinge ring formed on the upper side of the lower pressure plate, the outer diameter of the lower hinge ring is smaller than the outer diameter of the lower pressure plate, and the lower hinge rib is hinged on the lower hinge ring;

[0011] When the vertical reinforcement is in a contracted state, one end of the upper hinge reinforcement away from the upper anchor portion extends along the inclined direction toward the lower anchor portion, and one end of the lower hinge reinforcement away from the lower anchor portion extends along the inclined direction toward the upper anchor portion;

[0012] When the vertical reinforcement is in an open state, the side of the upper hinge reinforcement facing away from the lower anchoring portion can be pressed against the upper pressure plate, and the side of the lower hinge reinforcement facing away from the upper anchoring portion can be pressed against the lower pressure plate.

[0013] The above structure can smoothly make the vertical reinforcement move from the contracted state to the open state. Since the vertical reinforcement, the upper hinged reinforcement, the lower hinged reinforcement and the anchor cable group form a four-link structure with instability, the upper and lower pressure plates are used to squeeze and limit the upper and lower hinged reinforcements respectively, so as to fix the position of the vertical reinforcement when it is opened, and use this position as the set position of the vertical reinforcement when it is opened, thereby ensuring that the shape and strength of the enlarged head meet the set requirements.

[0014] Furthermore, in order to smoothly fix the lower anchoring part on each anchor cable, the lower anchoring part includes a lower pressure plate. Corresponding to each anchor cable, an anchor hole in the shape of a through hole is arranged on the lower pressure plate. The end of the anchor hole facing away from the upper anchoring part is formed as a conical hole with the small end facing the upper anchoring part. A clip group is arranged in the conical hole, and an extrusion plate is arranged on the side of the lower pressure plate facing away from the upper anchoring part. The locking bolt connects the extrusion plate to the lower pressure plate, and the extrusion plate tightly squeezes the clips in the clip group in the conical hole, so that the anchor cable is fixed to the lower pressure plate through the clip group.

[0015] The lower pressure plate and the clip group together form a clip-type anchor, which has the advantages of easy operation and stable clamping, and has become a conventional anchor for anchor cables. However, it requires the tension of the anchor cable to ensure that it locks the anchor cable. However, before the anchor cable is tensioned, the clip is in a relaxed state, and it is impossible to ensure that the lower anchoring part is stably maintained on the anchor cable. In this design, the clip is pre-compressed by the extrusion plate so that the clip locks the anchor cable on the lower anchoring part, preventing the lower anchoring part from slipping off the anchor cable, or part of the anchor cable coming off the lower anchoring part and failing to complete the subsequent prestressing.

[0016] Furthermore, corresponding to each anchor cable, there is a set of extrusion tubes provided on the anchor cable between the clamping plate and the clip group. The clamping plate presses the extrusion tube tightly on the clip, and the end of the clamping tube facing the clip only presses on the end face of the clip. In actual construction, the clip may be completely accommodated in the conical hole. At this time, the clamping plate alone cannot press the clip tightly in the conical hole, which may easily lead to insufficient locking force of the clip on the anchor cable, so that in the subsequent prestressing, the anchor cable may fall out of the anchor hole and the prestressing cannot be completed. Using a clamping tube to eliminate the above problems can ensure that the clip can lock the anchor cable tightly on the lower anchoring part.

[0017] Furthermore, in order to ensure that the step surface on the rotary jet drill pipe can smoothly push the upper anchoring part so that the vertical reinforcement reaches the open state, an elastic positioning mechanism is fixedly installed on the side of the upper anchoring part away from the lower anchoring part, and the elastic positioning mechanism includes at least one elastic positioner, and each elastic positioner includes a shell, a positioning rod and an elastic member, the shell has a guide cavity extending along the radial direction of the anchor cable hole, the guide cavity has an opening facing the direction of the central axis, the elastic member is arranged in the guide cavity, the positioning rod is slidably inserted into the guide cavity through the opening of the guide cavity, and compresses the elastic member; under the push of the elastic member, the end of the positioning rod away from the elastic member can be pressed against the rotary jet drill pipe, and when the rotary jet drill pipe retracts upward and the step surface reaches the upper side of the positioning rod, the positioning rod can be pressed against the reduced diameter section under the push of the elastic member, and the step surface can be pressed against the upper side of the positioning rod, so that the upper anchoring part can be pushed toward the lower anchoring part, so that the vertical reinforcement reaches the open state from the contracted state.

[0018] When the variable diameter steel cage rotary jet anchor cable structure is tilted, the lower end of the rotary jet drill rod will bend downward a small amount due to gravity. When the bend is large enough, the step surface can be pressed against the edge of the upper drill rod hole by utilizing the bend and the offset of the rotary jet drill rod. However, in the present application, the anchor cable hole is formed by the rotary jet process, and the anchor cable hole is filled with cement soil formed by a mixture of cement slurry and earthwork, which has a supporting effect on the rotary jet drill rod and can reduce the bending amount of the rotary jet drill rod. In addition, during actual construction, since it is impossible to directly observe the internal situation of the anchor cable hole, operations can only be performed based on experience, and the reliability is low. Using the bending and offset of the drill rod anchor cable to press the step surface against the edge of the upper drill rod hole often requires multiple operations to complete, and the construction efficiency is low.

[0019] The elastic member in the elastic locator is used to push the locating rod, forcing the locating rod to press against the outer peripheral surface of the reduced diameter section, so that the step surface can press against the upper side of the locating rod, thereby making the step surface indirectly press against the upper edge of the upper drill rod hole through the locating rod, ensuring that the jet-jet drill rod can push the upper anchoring part and make the vertical reinforcement reach the open state. Since the locating rod is surrounded by cement slurry, the thrust of the elastic member needs to be tested and tested during actual construction to ensure that the elastic member can overcome the resistance of the cement slurry and press the locating rod against the outer peripheral surface of the reduced diameter section. The elastic member can specifically be a cylindrical helical compression spring, a rubber block, an elastic sheet or other elastic member.

[0020] Furthermore, in order to completely wrap the lower end of the variable diameter steel cage in cement slurry, when the step surface is pressed against the upper edge of the lower drill rod hole, the lowest grouting hole on the jet grouting drill rod goes downward over the lower end surface of the vertical reinforcement when it is in the open state. According to different needs, the grouting holes of the jet grouting drill rod have different designs. In the axial direction of the jet grouting drill rod, one or more groups of grouting holes are provided. When only one group of grouting holes is provided, the group of grouting holes is the lowest grouting hole. The lower side of the variable diameter steel cage is grouted by the lowest grouting hole, so that the lower end of the variable diameter steel cage is completely wrapped in cement slurry.

[0021] Secondly, the present application also discloses a construction method of any of the above-mentioned variable diameter steel cage sprayed anchor cable structures, which comprises the following steps:

[0022] (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole;

[0023] (2) The jet grouting drill rod is pulled out, and then the reduced diameter section of the jet grouting drill rod is passed through the upper drill rod hole and the lower drill rod hole in sequence, and the step surface is pressed against the upper edge of the lower drill rod hole, and the steel structure with the vertical reinforcement in the contracted state is inserted into the anchor cable hole; when the reduced diameter steel cage reaches the set position of the anchor cable hole, the grouting hole of the jet grouting drill rod reaches the upper set position of the enlarged head, and then the cement slurry is continued to be sprayed to expand the anchor cable hole, and at the same time, the steel structure is continued to move downward until the grouting hole reaches the lower set position of the enlarged head;

[0024] Lift the jet grouting drill rod upwards, and when the step surface reaches the upper side of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole, and then push the upper anchoring part downwards to make the vertical reinforcement change from the contracted state to the open state, and then pull out the jet grouting drill rod;

[0025] (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

[0026] In the construction method, firstly, the anchor hole is formed by the rotary spraying method, so that the anchor hole is filled with cement soil formed by the mixture of cement slurry and earthwork, and the cement soil is used for support to avoid the collapse of the inner wall of the anchor hole, thereby avoiding the problem of the variable diameter steel cage being hindered from moving in the anchor hole and unable to reach the set position due to the collapse of the inner wall of the anchor hole in the dry anchor hole or the wet hole forming method using mud wall protection in the prior art.

[0027] This construction method is suitable for soil containing stone-like impurities that cannot be broken and can hinder the movement of the variable-diameter steel cage. In the process of the rotary jet drill rod pushing the variable-diameter steel cage to move, when the grouting hole of the rotary jet drill rod reaches the upper set position of the enlarged head, the cement slurry injection of the rotary jet drill rod is resumed, and while the anchor hole is enlarged to form the enlarged head cavity, the stone-like impurities in the anchor hole are stirred to eliminate the obstruction to the advancement of the variable-diameter steel cage until the grouting hole reaches the lower set position of the enlarged head. In this construction method, while pushing the variable-diameter steel cage to its set position, the rotary jet drill rod is used to expand the hole to form the enlarged head cavity.

[0028] In the process of pulling the jet jet drill rod out of the anchor hole, when the cement soil in the anchor section needs to be compacted, cement slurry can continue to be sprayed in the anchor section to compact the cement soil in the anchor section and improve the strength of the cement soil in the anchor section.

[0029] According to different requirements, the jet grouting drill rod can also be moved back and forth along its axial direction, and multiple reciprocating jet grouting can be carried out in the enlarged head of the variable diameter steel cage to further improve the density of the cement soil in the enlarged head of the variable diameter steel cage. When the jet grouting drill rod moves back and forth, the step surface cannot exceed the upper anchoring part, resulting in the jet grouting drill rod being unable to return again.

[0030] Furthermore, in step (2), while lifting the jet-jet drill rod upward, continue to spray cement slurry until the step surface reaches the upper side of the upper drill rod hole, and then stop spraying cement slurry to move the vertical reinforcement from a contracted state to an open state.

[0031] In this design, the process of the jet jet drill rod being lifted upward is utilized to continue spraying cement slurry for secondary hole expansion or to compact the cement soil in the expanded head to increase the strength of the expanded head until the step surface reaches the upper side of the upper drill rod hole, and then the step surface is used to open the vertical reinforcement.

[0032] Again, the present application also discloses another construction method of any of the above-mentioned variable diameter steel cage sprayed anchor cable structures, which comprises the following steps:

[0033] (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole;

[0034] (2) Pull out the jet grouting drill rod, then pass the reduced diameter section of the jet grouting drill rod through the upper drill rod hole and the lower drill rod hole in turn, and make the step surface press against the upper edge of the lower drill rod hole, and insert the steel structure with the vertical reinforcement in the contracted state into the anchor cable hole; when the reduced diameter steel cage reaches the set position of the anchor cable hole, the grouting hole of the jet grouting drill rod reaches the lower set position of the enlarged head, and then lift the jet grouting drill rod upward and continue to spray cement slurry until the step surface can press against the upper edge of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole, push the upper anchoring part downward, and make the vertical reinforcement change from the contracted state to the open state; pull out the jet grouting drill rod;

[0035] (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

[0036] In the construction method, firstly, the anchor hole is formed by the rotary spraying method, so that the anchor hole is filled with cement soil formed by the mixture of cement slurry and earthwork, and the cement soil is used for support to avoid the collapse of the inner wall of the anchor hole, thereby avoiding the problem of the variable diameter steel cage being hindered from moving in the anchor hole and unable to reach the set position due to the collapse of the inner wall of the anchor hole in the dry anchor hole or the wet hole forming method using mud wall protection in the prior art.

[0037] This construction method is suitable for soil that does not contain stone-like impurities that cannot be broken and can hinder the movement of the variable diameter steel cage. The rotary jet drill rod pushes the variable diameter stirrups to their set positions at one time, and while the rotary jet drill rod is lifted upward, cement slurry is sprayed to expand the hole to form an enlarged head cavity, and the injection of cement slurry in the enlarged head cavity is completed simultaneously.

[0038] In this construction method, it is necessary to set at least two groups of grouting holes arranged axially at intervals in the reduced diameter section, so that when the rotary jet drill rod is lifted upward and the step surface reaches the upper side of the upper anchoring part, the grouting holes located on the upper side can complete the formation of the upper part of the enlarged head, so that when the upper anchoring part is pushed to open the vertical reinforcement, there is enough space for accommodating the vertical reinforcement, thereby avoiding the vertical reinforcement from being unable to be fully opened, affecting the strength of the enlarged head.

[0039] In the process of pulling the jet jet drill rod out of the anchor hole, when the cement soil in the anchor section needs to be compacted, cement slurry can continue to be sprayed in the anchor section to compact the cement soil in the anchor section and improve the strength of the cement soil in the anchor section.

[0040] According to different requirements, the jet grouting drill rod can also be moved back and forth along its axial direction, and multiple reciprocating jet grouting can be carried out in the enlarged head of the variable diameter steel cage to further improve the density of the cement soil in the enlarged head of the variable diameter steel cage. When the jet grouting drill rod moves back and forth, the step surface cannot exceed the upper anchoring part, resulting in the jet grouting drill rod being unable to return again.

[0041] Furthermore, in step (2), after the vertical reinforcement reaches the open state, the jet grouting drill rod is lifted upward and cement slurry is continuously sprayed until the upper set position of the enlarged head is reached.

[0042] In this design, the process of the jet-jet drill rod being lifted upward is utilized to continue to spray cement slurry, perform secondary hole expansion or compact the cement soil in the expanded head, and improve the strength of the expanded head. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of an embodiment of a variable diameter steel cage rotary sprayed anchor cable structure.

[0044] Figure 2 yes Figure 1 Enlarged view of part A.

[0045] Figure 3 yes Figure 2 Enlarged view of part B.

[0046] Figure 4 yes Figure 3 Another state diagram of .

[0047] Figure 5 yes Figure 3 Enlarged view of part D.

[0048] Figure 6 yes Figure 2 Magnified view of part C.

[0049] Figure 7 yes Figure 6 The view from the EE direction.

[0050] Figure 8 This is the attached picture when the vertical reinforcement is in the contracted state. DETAILED DESCRIPTION

[0051] Example 1

[0052] The following first describes the structure of the variable diameter steel cage rotary spray anchor cable structure. Figure 1-Figure 7 Along the length direction, the variable diameter steel cage rotary spray anchor cable structure includes an enlarged head section, a common anchoring section and a free section connected in sequence, wherein the enlarged head section and the common anchoring section are collectively referred to as the anchoring section, and the diameters of the common anchoring section and the free section are roughly the same. Figure 1 In the figure, the region of the enlarged head section is marked as S, the region of the common anchoring section is marked as M, and the region of the free section is marked as N. The enlarged head 12 described below forms the enlarged head section.

[0053] The variable diameter steel cage rotary spray anchor cable structure includes a steel structure 200 inserted into the anchor cable hole 10 and cement soil wrapped on the steel structure. The anchor cable hole is formed by a rotary spray process. To simplify the drawings, the cement soil is not shown in the drawings. The anchor cable hole 10 includes a rod section 11 and an enlarged head 12 located at the lower end of the rod section 11. For ease of description, the chamber formed by the outer peripheral surface of the enlarged head is called the enlarged head cavity. The enlarged head cavity in this application is slightly different from the enlarged head cavity in the prior art. In this application, the enlarged head cavity is formed when the enlarged head cavity is formed, and the cement slurry in the enlarged head cavity is injected at the same time, and the cement slurry is mixed with the earth to form cement soil. In the prior art, the enlarged head cavity is formed first, and then the enlarged head steel cage is placed in the enlarged head cavity, and finally cement slurry or concrete is injected into the enlarged head cavity. The variable diameter steel cage rotary sprayed anchor cable structure in this embodiment is inclined, and the angle between it and the horizontal plane is 45°. It can be understood that in other embodiments, according to different requirements, the inclination angle can also be 30°, 40°, 60°, and of course it can also be vertical or horizontal, or other angles between 0-90°.

[0054] The steel structure 200 includes an anchor cable group and a variable diameter steel cage 20, wherein the variable diameter steel cage 20 is located in the enlarged head. The variable diameter steel cage 20 includes a lower anchoring portion 30, an upper anchoring portion 40 and a vertical reinforcement group. The anchor cable group includes four anchor cables 201 that are parallel to each other and extend along the axial direction of the anchor cable hole. One end of each anchor cable 201 facing the same direction is formed as an anchor end 202, and the other end away from the anchor end is formed as a tensioning end 203, wherein the tensioning end 203 extends outward from the anchor cable hole 10.

[0055] The four anchor cables are arranged at intervals around the central axis 110 , and the anchoring end 202 of each anchor cable 201 is fixed on the lower anchoring part 30 , and each anchor cable freely passes through the upper anchoring part 40 , and the upper anchoring part 40 is located on the upper side of the lower anchoring part 30 .

[0056] Specifically in this embodiment, please refer to Figure 3 The upper anchoring part 40 includes an upper pressure plate 41 and an upper hinge ring 46 formed on the lower side of the upper pressure plate, and the outer diameter of the upper hinge ring is smaller than the outer diameter of the upper pressure plate. The upper anchoring part is provided with an upper drill rod hole 411, and the upper drill rod hole 411 is a through hole, and penetrates the upper surface of the upper pressure plate upwardly and penetrates the lower surface of the upper hinge ring downwardly. Corresponding to each anchor cable 201, a sliding hole 42 in the form of a through hole is provided on the upper pressure plate 41, and in the radial direction, the sliding hole is located on the outer side of the upper hinge ring, so that the upper hinge ring will not cause obstruction to the sliding hole. The upper pressure plate 41 is freely mounted on the anchor cable through the sliding hole, so that the upper anchoring part is slidably mounted on the anchor cable.

[0057] See also Figure 6The lower anchoring part 30 includes a lower pressure plate 31 and a lower hinge ring 36 formed on the upper side of the lower pressure plate, and the outer diameter of the lower hinge ring is smaller than the outer diameter of the lower pressure plate. A lower drill rod hole 311 is provided on the lower anchoring part, and the lower drill rod hole 311 is a through hole and penetrates upwardly through the lower surface of the lower pressure plate and the upper surface of the lower hinge ring. The upper drill rod hole is coaxially arranged with the lower drill rod hole in the extending direction of the anchor cable hole.

[0058] The vertical reinforcement group includes 4 vertical reinforcements 21 arranged at intervals around the anchor cable group, and each vertical reinforcement 21 has an upper hinge reinforcement 47 and a lower hinge reinforcement 37. The two ends of the upper hinge reinforcement 47 are respectively hinged to the upper hinge ear 48 and the upper hinge ring of the corresponding vertical reinforcement, and the two ends of the lower hinge reinforcement 37 are respectively hinged to the lower hinge ear 38 and the lower hinge ring of the corresponding vertical reinforcement.

[0059] When the vertical bar is in the contracted state, the end of the upper hinge bar away from the upper anchorage extends along the inclined direction toward the lower anchorage, and the end of the lower hinge bar away from the lower anchorage extends along the inclined direction toward the upper anchorage. When the vertical bar is in the open state, the side of the upper hinge bar away from the lower anchorage can press against the upper pressure plate, and the side of the lower hinge bar away from the upper anchorage can press against the lower pressure plate. Please also participate Figure 3 and Figure 8 ,in Figure 8 This is the attached picture when the vertical reinforcement is in the contracted state. Figure 3 The figure is a diagram showing the vertical ribs in an open state. Pushing the upper anchoring portion 40 toward the lower anchoring portion 30 can move the vertical ribs from a contracted state to an open state.

[0060] The lower end of the rod body 61 of the jet grouting drill rod 60 is reduced in diameter along the radial direction to form a reduced diameter section 62 and a step surface 63 facing the lower end surface of the jet grouting drill rod, see Figure 6 The reduced diameter section 62 can pass through the upper drill rod hole and the lower drill rod hole in sequence, and make the step surface 63 press against the upper edge of the lower drill rod hole to deliver the steel structure into the anchor cable hole.

[0061] After the steel structure is sent into the anchor hole, the anchor hole is expanded by spraying cement slurry with a jet jet drill rod to form an enlarged head cavity, and the variable diameter steel cage is located in the enlarged head cavity, and then the jet jet drill rod is lifted upward, and the step surface is pressed against the upper edge of the upper drill rod hole, and the upper anchoring part is pushed toward the lower anchoring part, so that the vertical reinforcement changes from the contracted state to the open state. The soft rope stirrup 22 is wound around the vertical reinforcement group. In this embodiment, the soft rope stirrup is specifically made of steel wire rope, and the steel wire rope is fixed to the vertical reinforcement with a fastener. It can be understood that in other embodiments, the steel wire rope can also be fixed to the vertical reinforcement with steel wire or galvanized iron wire. When the vertical reinforcement is in the open state, the vertical reinforcement can fully open the soft rope stirrup to tighten the soft rope stirrup. When the vertical reinforcement is in the contracted state, the soft rope stirrup can be bent and accommodated inward in the space surrounded by the vertical reinforcement.

[0062] In order to smoothly use the jet grouting drill rod to open the vertical reinforcement, in this embodiment, an elastic positioning mechanism is fixedly installed on the side of the upper pressure plate 41 of the upper anchoring part 40 away from the lower anchoring part 30. In this embodiment, the elastic positioning mechanism includes three elastic positioners 50, which are evenly spaced around the upper drill rod hole 411. Please also refer to Figure 5 Each elastic locator 50 includes a housing 51, a positioning rod 53 and an elastic member 54. The housing has a guide cavity 52 extending radially along the anchor hole. The guide cavity 52 has an opening facing the central axis. The elastic member is arranged in the guide cavity. The positioning rod is inserted into the guide cavity through the opening of the guide cavity and compresses the elastic member. Under the push of the elastic member, the end of the positioning rod away from the elastic member can be pressed against the jet grouting drill rod. When the jet grouting drill rod retracts upward and the step surface reaches the upper side of the positioning rod, the positioning rod can be pressed against the reduced diameter section under the push of the elastic member, and the step surface can be pressed against the upper side of the positioning rod. At this time, the step surface is indirectly pressed against the upper edge of the upper drill rod hole through the positioning rod. Pushing the drill rod downward can push the upper anchoring part toward the lower anchoring part, so that the vertical ribs are changed from the contracted state to the open state. The elastic member is specifically a cylindrical helical compression spring. It can be understood that in other embodiments, the elastic member can also be a rubber block or an elastic sheet. In order to prevent cement slurry from entering the guide cavity, an O-type rubber ring is embedded on the inner wall at the outlet of the guide cavity 52, but the O-type rubber ring is not shown in the drawings.

[0063] The elastic positioning mechanism is to enable the step surface to smoothly press the positioning rod against the edge of the upper drill rod hole. When the step surface can smoothly press against the edge of the upper drill rod hole, the elastic positioning mechanism can be cancelled. For example, when the variable diameter steel cage rotary grouting anchor cable structure is inclined, and in this inclined state, the rotary grouting drill rod is bent due to gravity, and it can ensure that the step surface presses against the edge of the upper anchor hole, the elastic positioning mechanism can be cancelled. However, when it cannot ensure that the step surface presses against the edge of the upper anchor hole, it is best to retain the elastic positioning mechanism.

[0064] In order to facilitate the fixing of the anchor cable on the lower anchoring part, in this embodiment, a through-hole-shaped anchor hole is provided on the lower pressure plate 31 corresponding to each anchor cable 201. The end of the anchor hole away from the upper anchoring part is formed into a conical hole 312 with the small end facing the upper anchoring part. The clip group 32 is arranged in the conical hole. An extrusion plate 34 is provided on the side of the lower pressure plate away from the upper anchoring part. The locking bolt 35 passes through the lower pressure plate 31 and is screwed on the extrusion plate 34 to connect the extrusion plate to the lower pressure plate, and the extrusion plate tightly squeezes the clips in the clip group into the conical hole, so that the anchor cable is fixed to the lower pressure plate through the clip. A through-hole-shaped rod hole 341 is provided on the extrusion plate 34, and the reduced diameter section of the jet drilling rod 60 can pass through the rod hole downward. In the radial direction, the anchor hole is located on the outer side of the lower hinge ring, so that the lower hinge ring will not hinder the anchor hole.

[0065] In order to ensure that the clamp can be squeezed with a set strength and avoid the clamp being completely contained in the conical hole and thus failing to secure the anchor cable, a squeezing tube 33 sleeved on the anchor cable is provided between the clamping plate and the clamp assembly, and the clamping plate tightly presses the squeezing tube 33 on the clamp. The end of the squeezing tube facing the clamp only presses against the end surface of the clamp.

[0066] In order to ensure that the variable diameter steel cage is completely wrapped in cement slurry, a grouting hole is provided at the bottom of the reduced diameter section. When the step surface is pressed against the upper edge of the lower drill rod hole, the grouting hole at the lowest end of the jet jet drill rod goes downward beyond the lower end surface of the vertical reinforcement when in the open state. It can be understood that in other embodiments, at least two groups of grouting holes can be provided radially on the reduced diameter section, one of which is located at the lower end of the reduced diameter section.

[0067] The following is an explanation of the construction method of the variable diameter steel cage sprayed anchor cable structure, which specifically includes two construction methods, which are described as follows:

[0068] Example 2

[0069] The first construction method, the steps are as follows:

[0070] (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole;

[0071] (2) The jet grouting drill rod is pulled out, and then the reduced diameter section of the jet grouting drill rod is passed through the upper drill rod hole and the lower drill rod hole in turn, and the step surface is pressed against the upper edge of the lower drill rod hole, and the steel structure with the vertical reinforcement in the contracted state is inserted into the anchor hole; when the variable diameter steel cage reaches the set position of the anchor hole, the grouting hole of the jet grouting drill rod reaches the upper set position of the enlarged head, and then the cement slurry is continued to be sprayed to expand the anchor hole, and at the same time, the steel structure is continued to move downward until the grouting hole reaches the lower set position of the enlarged head, and when the enlarged head cavity is formed, the grouting in the enlarged head cavity is completed at the same time.

[0072] Lift the jet grouting drill rod upwards. When the step surface reaches the upper side of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole. Then push the upper anchoring part downwards to make the vertical reinforcement move from the contracted state to the open state, and pull out the jet grouting drill rod.

[0073] In order to compact the cement soil in the enlarged head cavity and ensure its strength, in another embodiment, while lifting the rotary jet drill rod upward, cement slurry can continue to be sprayed until the step surface reaches the upper side of the upper drill rod hole, and then the cement slurry spraying is stopped to change the vertical reinforcement from the contracted state to the open state.

[0074] According to needs, cement slurry can be continuously sprayed on the anchoring section while the rotary jet drill rod is being pulled out, so as to improve the bonding strength of the anchoring section.

[0075] (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

[0076] It can be understood that according to different requirements, in other embodiments, after the variable diameter steel cage is sent to its set position, the rotary jet drill rod can also be reciprocated along its axial direction, and multiple reciprocating rotary jetting can be performed in the enlarged head of the variable diameter steel cage to further improve the density of the cement soil in the enlarged head of the variable diameter steel cage. When the rotary jet drill rod moves back and forth, the step surface cannot exceed the upper anchoring part, resulting in the rotary jet drill rod being unable to return again.

[0077] Example 3

[0078] The second construction method, the steps are as follows:

[0079] (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole;

[0080] (2) Pull out the jet grouting drill rod, then pass the reduced diameter section of the jet grouting drill rod through the upper drill rod hole and the lower drill rod hole in turn, and make the step surface press against the upper edge of the lower drill rod hole, and insert the steel structure with the vertical reinforcement in the contracted state into the anchor cable hole; when the reduced diameter steel cage reaches the set position of the anchor cable hole, the grouting hole of the jet grouting drill rod reaches the lower set position of the enlarged head, and then lift the jet grouting drill rod upward, and continue to spray cement slurry until the step surface can press against the upper edge of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole, and push the upper anchoring part downward, so that the vertical reinforcement changes from the contracted state to the open state.

[0081] After the vertical reinforcement reaches the open state, lift the jet grouting drill rod upward and continue to spray cement slurry until the upper side setting position of the expanded head is reached. Pull out the jet grouting drill rod.

[0082] According to needs, cement slurry can be continuously sprayed on the anchoring section while the rotary jet drill rod is being pulled out, so as to improve the bonding strength of the anchoring section.

[0083] (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

[0084] In this embodiment, two groups of grouting holes are arranged on the rotary jet drill rod at intervals along the axial direction. When the step surface is located on the upper side of the upper anchoring part, the grouting holes located on the upper side can complete the formation of the upper part of the enlarged head cavity, so that when the vertical reinforcement is opened, the vertical reinforcement can reach the open state, thereby ensuring the strength of the enlarged head.

[0085] It can be understood that according to different requirements, in other embodiments, after the variable diameter steel cage is sent to its set position, the rotary jet drill rod can also be reciprocated along its axial direction, and multiple reciprocating rotary jetting can be performed in the enlarged head of the variable diameter steel cage to further improve the density of the cement soil in the enlarged head of the variable diameter steel cage. When the rotary jet drill rod moves back and forth, the step surface cannot exceed the upper anchoring part, resulting in the rotary jet drill rod being unable to return again.

Claims

1. A variable diameter steel cage rotary spray anchor cable structure, characterized in that: It comprises a steel structure inserted into an anchor hole and cement soil wrapped on the steel structure, wherein the anchor hole is formed by a rotary spraying process; the steel structure comprises an anchor group and a variable diameter steel cage, wherein the variable diameter steel cage is located in the enlarged head of the anchor hole; the variable diameter steel cage comprises a lower anchoring portion, an upper anchoring portion and a vertical reinforcement group, the anchor group comprises 2-10 anchor cables which are parallel to each other and extend along the axial direction of the anchor hole, one end of each anchor cable facing the same direction is formed as an anchoring end, and the other end away from the anchoring end is formed as a tensioning end, the 2-10 anchor cables are arranged at intervals around a central axis, the anchoring ends of each anchor cable are fixed on the lower anchoring portion, and each anchor cable freely passes through the upper anchoring portion, and the upper anchoring portion is located on the upper side of the lower anchoring portion; The vertical bar group includes a plurality of vertical bars arranged at intervals around the anchor cable group, and each vertical bar has an upper hinged bar and a lower hinged bar corresponding to each vertical bar, the two ends of the upper hinged bar are respectively hinged to the upper part and the upper anchoring part of the corresponding vertical bar, and the two ends of the lower hinged bar are respectively hinged to the lower part and the lower anchoring part of the corresponding vertical bar; pushing the upper anchoring part toward the lower anchoring part can make the vertical bar move from a contracted state to an open state; The upper anchoring part is provided with an upper drill rod hole, and the lower anchoring part is provided with a lower drill rod hole, and the upper drill rod hole and the lower drill rod hole are coaxially arranged in the extending direction of the anchor hole; the lower end of the rod body of the rotary jet drill rod is radially reduced to form a reduced diameter section and a step surface facing the lower end surface of the rotary jet drill rod, and the reduced diameter section can pass through the upper drill rod hole and the lower drill rod hole in sequence, and the step surface is pressed against the upper side edge of the lower drill rod hole to send the steel structure into the anchor hole; after the steel structure is sent into the anchor hole, cement slurry is sprayed by the rotary jet drill rod to expand the hole to form an enlarged head cavity, and then the rotary jet drill rod is lifted upward, and the step surface is pressed against the upper side edge of the upper drill rod hole, and the upper anchoring part is pushed toward the lower anchoring part, so that the vertical reinforcement changes from a contracted state to an open state; the soft rope stirrup is wound around the vertical reinforcement group; at least a grouting hole is provided at the lower end of the reduced diameter section.

2. The variable diameter steel cage rotary spray anchor cable structure according to claim 1 is characterized in that: The upper anchoring portion includes an upper pressure plate and an upper hinge ring formed on the lower side of the upper pressure plate, the outer diameter of the upper hinge ring is smaller than the outer diameter of the upper pressure plate, and the upper hinge rib is hinged on the upper hinge ring; The lower anchoring part includes a lower pressure plate and a lower hinge ring formed on the upper side of the lower pressure plate, the outer diameter of the lower hinge ring is smaller than the outer diameter of the lower pressure plate, and the lower hinge rib is hinged on the lower hinge ring; When the vertical reinforcement is in a contracted state, one end of the upper hinge reinforcement away from the upper anchor portion extends along the inclined direction toward the lower anchor portion, and one end of the lower hinge reinforcement away from the lower anchor portion extends along the inclined direction toward the upper anchor portion; When the vertical reinforcement is in an open state, the side of the upper hinge reinforcement facing away from the lower anchoring portion can be pressed against the upper pressure plate, and the side of the lower hinge reinforcement facing away from the upper anchoring portion can be pressed against the lower pressure plate.

3. The variable diameter steel cage rotary spray anchor cable structure according to claim 1 is characterized in that: The lower anchoring part includes a lower pressure plate, and corresponding to each anchor cable, an anchor hole in the shape of a through hole is arranged on the lower pressure plate, and the end of the anchor hole away from the upper anchoring part is formed as a conical hole with the small end facing the upper anchoring part, and a clip group is arranged in the conical hole. An extrusion plate is arranged on the side of the lower pressure plate away from the upper anchoring part, and the locking bolt connects the extrusion plate to the lower pressure plate, and the extrusion plate tightly squeezes the clips in the clip group in the conical hole, so that the anchor cable is fixed to the lower pressure plate through the clip group.

4. The variable diameter steel cage rotary spray anchor cable structure according to claim 3 is characterized in that: Corresponding to each anchor cable, there is a set of extrusion tubes arranged on the anchor cable between the clamping plate and the clamping piece group. The clamping plate presses the extrusion tube tightly on the clamping piece, and one end of the clamping tube facing the clamping piece only presses on the end surface of the clamping piece.

5. The variable diameter steel cage rotary spray anchor cable structure according to claim 1 is characterized in that: An elastic positioning mechanism is fixedly installed on the side of the upper anchoring part away from the lower anchoring part, and the elastic positioning mechanism includes at least one elastic positioning device, each elastic positioning device includes a shell, a positioning rod and an elastic member, the shell has a guide cavity extending radially along the anchor hole, the guide cavity has an opening facing the direction of the central axis, the elastic member is arranged in the guide cavity, the positioning rod is slidably inserted into the guide cavity through the opening of the guide cavity, and compresses the elastic member; under the push of the elastic member, the end of the positioning rod away from the elastic member can be pressed against the rotary jet drill rod, and when the rotary jet drill rod retracts upward and makes the step surface reach the upper side of the positioning rod, the positioning rod can be pressed against the reduced diameter section under the push of the elastic member, and the step surface can be pressed against the upper side of the positioning rod, so as to be able to push the upper anchoring part toward the lower anchoring part, so that the vertical reinforcement reaches the open state from the contracted state.

6. The variable diameter steel cage rotary spray anchor cable structure according to claim 1 is characterized in that: When the step surface is pressed against the upper edge of the lower drill rod hole, the grouting hole located at the lowermost end of the jet jet drill rod goes downward over the lower end surface of the vertical reinforcement in the open state.

7. The construction method of the variable diameter steel cage rotary spray anchor cable structure according to any one of claims 1 to 6, characterized in that: The steps include: (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole; (2) The jet grouting drill rod is pulled out, and then the reduced diameter section of the jet grouting drill rod is passed through the upper drill rod hole and the lower drill rod hole in sequence, and the step surface is pressed against the upper edge of the lower drill rod hole, and the steel structure with the vertical reinforcement in the contracted state is inserted into the anchor cable hole; when the reduced diameter steel cage reaches the set position of the anchor cable hole, the grouting hole of the jet grouting drill rod reaches the upper set position of the enlarged head, and then the cement slurry is continued to be sprayed to expand the anchor cable hole, and at the same time, the steel structure is continued to move downward until the grouting hole reaches the lower set position of the enlarged head; Lift the jet grouting drill rod upwards, and when the step surface reaches the upper side of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole, and then push the upper anchoring part downwards to make the vertical reinforcement change from the contracted state to the open state, and then pull out the jet grouting drill rod; (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

8. The construction method according to claim 8, characterized in that: In step (2), while lifting the jet-jet drill rod upward, continue to spray cement slurry until the step surface reaches the upper side of the upper drill rod hole, then stop spraying cement slurry and move the vertical reinforcement from a contracted state to an open state; then continue to lift the jet-jet drill rod upward and continue to spray cement slurry in the anchoring section.

9. The construction method of the variable diameter steel cage rotary spray anchor cable structure according to any one of claims 1 to 6, characterized in that: The steps include: (1) Use the jet-jet drill pipe to spray cement slurry to construct the anchor hole; (2) Pull out the jet grouting drill rod, then pass the reduced diameter section of the jet grouting drill rod through the upper drill rod hole and the lower drill rod hole in turn, and make the step surface press against the upper edge of the lower drill rod hole, and insert the steel structure with the vertical reinforcement in the contracted state into the anchor cable hole; when the reduced diameter steel cage reaches the set position of the anchor cable hole, the grouting hole of the jet grouting drill rod reaches the lower set position of the enlarged head, and then lift the jet grouting drill rod upward and continue to spray cement slurry until the step surface can press against the upper edge of the upper drill rod hole, press the step surface against the upper edge of the upper drill rod hole, push the upper anchoring part downward, and make the vertical reinforcement change from the contracted state to the open state; pull out the jet grouting drill rod; (3) When the cement soil in the anchor hole reaches the set strength, the anchor cables of the anchor cable group are tensioned to generate prestress and anchor; the variable diameter steel cage and the surrounding cement soil together form an enlarged head.

10. The construction method according to claim 9, characterized in that: In step (2), after the vertical reinforcement reaches the open state, the jet grouting drill rod is lifted upward and cement slurry is continuously sprayed until the upper set position of the enlarged head is reached.

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