Permanent and temporary combined prestressed anchor rod structure

Abstract

The utility model provides a kind of permanent and temporary combination prestressed anchor rod structure, including multistage anchor rod structure, the multistage anchor rod structure is sequentially from bottom to top anchorage section, free section one, anchor head one, free section two, anchor head two.The utility model can reduce anchor rod engineering quantity, construction difficulty and safety risk reduce, ensure that lining structure is stable and safe, reduce rock mass broken hole and side slope disturbance problem;Ensure that anchor rod structure is combined into complete unit with concrete, reduce tensioning prestress loss, ensure grouting full and dense, ensure construction quality, reduce engineering cost.

Description

Technical Field

[0001] This utility model relates to the field of foundation pit slope protection technology, and more specifically, to a permanent and temporary combined prestressed anchor structure. Background Technology

[0002] A typical prestressed anchor structure consists of three parts: the anchor head, the free section, and the anchoring section. The anchoring force generated by the anchor head applies a certain prestress to the surrounding rock, actively reinforcing the surrounding rock. It is a common method of reinforcement and support used in engineering construction such as slopes and deep foundation pits.

[0003] The building structure uses prestressed anchored lining walls, but the foundation pit is different. During the excavation of the foundation pit, temporary support is required for the pit slope to ensure construction safety. If prestressed anchors are used for reinforcement separately, the project will involve a large number of anchors, be difficult to construct, have a long construction period, and be costly. The design adopts a prestressed anchored lining wall structure, which is generally best suited for foundation pit slopes of 65° or higher, and relatively fractured rock masses, to reduce the amount of concrete filling behind the lining wall. Based on general prestressed anchor structures, researching new prestressed anchor combination structures according to application characteristics and requirements is of great significance.

[0004] Chinese patent application CN 202023170563.5 discloses a steel pipe pile and anchor cable combined support structure. The anchor cable includes a free section and an anchoring section. The steel pipe pile wraps around the free section of the anchor cable. The top of the free section of the anchor cable and the top of the steel pipe pile are fixed by a fixing platform, which contains a grouting pipe for grouting. While this structure uses a multi-segment anchor cable configuration, it has the following problems: If the free section of the anchor cable wrapped by the steel pipe pile is not pulled out, it still increases the cost of the anchor cable project if there is no specific design requirement for slope slippage. Furthermore, during grouting of the anchoring section, grout may enter through several grout outlet holes on the steel pipe pile, affecting the length of the free section. After the anchor cable is tensioned and locked, when supplementary grouting is performed, the lack of grout return and venting holes on the steel pad affects the fullness and density of the grout, making it difficult to guarantee quality. Utility Model Content

[0005] The purpose of this invention is to address the technical problems existing in the prior art by providing a permanent and temporary combined prestressed anchor structure. It employs a prestressed anchor assembly structure with multiple anchor segments, and utilizes a two-stage prestress control construction method to achieve a permanent and temporary combined reinforcement effect for foundation pit slope support and lining wall anchoring.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] A permanent and temporary combined prestressed anchor structure includes a multi-segment anchor structure, wherein the multi-segment anchor structure is, from bottom to top, an anchoring segment, a free segment one, an anchor head one, a free segment two, and an anchor head two;

[0008] The anchoring section is an anchor body used to transfer the tensile force of the slope support and lining structure to the surrounding strata. The anchor body is formed by bonding the anchor rod body to the soil and rock with cement grout or cement mortar.

[0009] The free section one includes an anchor rod body located between the anchoring section and the anchor head one. The outer side of the anchor rod body is fitted with a smooth round plastic tube that is sealed to the anchoring section. The upper end is connected to the anchor rod body of the free section two through a connector. The length of the free section one is not less than 5m.

[0010] The smooth plastic tube and the anchoring section are sealed by wrapping an outer layer of engineering tape.

[0011] The anchor head is used to transfer the tension from the anchor body to the foundation pit slope. It includes a reinforced concrete base, a pad plate, and an anchor. The reinforced concrete base is connected to the slope mesh spraying or protective net to form a temporary support structure for the foundation pit slope. The pad plate is connected to a grouting pipe and a grout return and venting pipe. The grouting pipe is connected to the bottom of the smooth plastic pipe, and the grout return and venting pipe is connected to the top of the inside of the smooth plastic pipe.

[0012] The second free section includes an anchor body located between anchor head one and anchor head two. A corrugated steel pipe is sleeved on the outside of the anchor body. Both ends of the corrugated steel pipe are sealed to the pads of the two anchor heads. The lower end of the anchor body is connected to the anchor body of the first free section through a connector. The length of the second free section is determined according to the anchor structure position, slope angle, and lining structure thickness. Its total length with the first free section accounts for 1 / 3 to 1 / 2 of the total length of the anchor body.

[0013] The second anchor head is used to transfer the tension from the rod body to the lining structure. It includes a pad plate, an anchor, and a sealing anchor body. The pad plate is pre-embedded in the lining structure. A grouting pipe and a grout return and venting pipe are connected to the pad plate. The grouting pipe is connected to the bottom of the corrugated steel pipe and is connected and communicates with the grouting pipe on the pad plate of the first anchor head. The grout return and venting pipe is connected to the top of the inside of the corrugated steel pipe.

[0014] This invention achieves a permanent and temporary reinforcement effect for foundation pit slope support and lining wall anchoring, reducing the number of anchor bolt projects; the foundation pit excavation and anchor bolt structure are constructed in layers from top to bottom, while the lining structure and anchor bolt extension are constructed in layers from bottom to top, reducing construction difficulty and safety risks; the filling concrete construction is convenient, and the stability and safety of the lining structure are ensured by pre-tensioning and timely adjustment of the pre-tension force. Meanwhile, the first free section is sealed with a smooth round plastic pipe, isolated from the anchoring section, and grouting is carried out at the bottom of the hole in time before the foundation concrete construction. The outer sides of both the anchoring section and the first free section are filled with grout, reducing the problems of rock mass fracture and hole collapse and slope disturbance. The second free section is sealed with a corrugated steel pipe, which has a very strong bond with the concrete, ensuring that the anchor structure and the concrete are integrated into a complete whole. The second free section and the first free section are grouted together, so that when the second anchor head is tensioned, the total length of the free section is not less than 5m, reducing the loss of prestress during tensioning. The smooth round plastic pipe of the first free section and the corrugated steel pipe of the second free section are connected through grouting pipes and grout return and venting pipes to ensure full and dense grouting and guarantee construction quality. Overall, the construction method of this permanent and temporary combined prestressed anchor structure has accelerated the project progress, ensured project quality and safety, and reduced project costs. Attached Figure Description

[0015] Figure 1 This is a cross-sectional schematic diagram of the implementation effect of the permanent and temporary combined prestressed anchor structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the prestressed anchor structure of this utility model. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Example 1

[0019] like Figure 1 , Figure 2 As shown, the cross-section of the permanent and temporary combined prestressed anchor structure of this utility model includes a prestressed anchor structure 1, a foundation pit slope 2, a lining structure 3, and filling concrete 4. The prestressed anchor structure 1 includes a multi-segment anchor structure, which, from bottom to top, consists of anchoring segment 1-1, free segment 1-2, anchor head 1-3, free segment 2-4, and anchor head 2-5.

[0020] The anchoring section 1-1 is an anchor body used to transfer the tension of the slope support and lining structure 3 to the surrounding strata. The anchor body is formed by bonding the anchor rod body 5 to the soil and rock with cement grout or cement mortar.

[0021] The free section 1-2 includes an anchor rod body 5 located between the anchoring section 1-1 and the anchor head 1-3. The outer side of the anchor rod body 5 is fitted with a smooth round plastic tube 9 that is sealed to the anchoring section 1-1. The upper end is connected to the anchor rod body 5 of the free section 1-4 through a connector 6. The length of the free section 1-2 is not less than 5m.

[0022] The smooth plastic tube 9 and the anchoring section 1-1 are sealed by wrapping engineering tape around them.

[0023] The anchor head 1-3 is used to transfer the tension from the anchor body 5 to the foundation pit slope 2. It includes a reinforced concrete base 13, a pad 7, and an anchor 8. The reinforced concrete base 13 is connected to the slope mesh spraying or protective net to form a temporary support structure for the foundation pit slope. The pad 7 is connected to a grouting pipe 11 and a grout return and venting pipe 12. The grouting pipe 11 is connected to the bottom of the smooth plastic pipe 9, and the grout return and venting pipe 12 is connected to the top of the inside of the smooth plastic pipe 9.

[0024] The free section 2 1-4 includes an anchor body 5 located between anchor head 1-3 and anchor head 2 1-5. A corrugated steel pipe 10 is sleeved on the outside of the anchor body 5. Both ends of the corrugated steel pipe 10 are sealed to the pads 7 of the two anchor heads. The lower end of the anchor body 5 is connected to the anchor body 5 of free section 1-2 through a connector 6. The length of free section 2 1-4 is determined according to the position of the anchor structure 1, the slope angle, and the thickness of the lining structure 3. Its total length with free section 1-2 accounts for 1 / 3 to 1 / 2 of the total length of the anchor body 5.

[0025] The second anchor 1-5 is used to transfer the tension from the rod body to the lining structure 3, including a pad 7, an anchor 8, and a sealing anchor body 14. The pad 7 is pre-embedded in the lining structure 3. A grouting pipe 11 and a grout return and venting pipe 12 are connected to the pad 7. The grouting pipe 11 is connected to the bottom of the corrugated steel pipe 10 and is connected and communicates with the grouting pipe 11 on the pad 7 of the first anchor 1-3. The grout return and venting pipe 12 is connected to the top of the inside of the corrugated steel pipe 10. The sealing anchor body 14 is integrated with the lining structure 3 to seal the anchor 8.

[0026] Example 2

[0027] like Figure 1 , Figure 2 As shown, a construction method for a combined permanent and temporary prestressed anchor structure includes the following two stages:

[0028] S1: Construction of the foundation pit slope 2. The foundation pit is excavated in layers from top to bottom. The prestressed anchor structure 1 is constructed in layers. The first anchor tensioning is carried out, and temporary anchoring is performed without grouting. The slope of this layer is then covered with mesh and shotcrete or protective netting.

[0029] S2: Lining structure 3 construction. After the foundation pit is excavated to the bottom layer, the lining structure is poured in layers from bottom to top, and the filling concrete 4 is poured in a timely manner. The prestressed anchor structure 1 is extended in layers, the second anchor tensioning is carried out, and the anchoring, grouting and sealing are completed.

[0030] The specific construction method for S1 includes the following steps:

[0031] S11: Anchor bolt hole drilling. Excavation shall be stopped 0.5m below the design elevation of the prestressed anchor bolt structure 1. The coordinate positions of the anchor holes in each anchoring section 1-1 and free section 1-2 shall be measured, and the holes shall be drilled using a drilling rig and cleaned thoroughly.

[0032] S12: Anchor rod fabrication and installation, anchor hole grouting. The anchor rod of free section 1-2 is fitted with a smooth round plastic tube 9, and sealed and fixed with engineering tape wrapped around it; the fabricated anchor rod is placed into the anchor hole, the grout is injected from the bottom of the hole, and the air is discharged from the anchor rod hole. The anchor holes on the outside of anchor section 1-1 and free section 1-2 are fully and densely grouted.

[0033] S13: Construction of Anchor Head 1-3 Structure. First, tie the reinforcing bars of the reinforced concrete base 13 and reserve the connecting bars for the slope mesh shotcrete reinforcement; the anchor head 1-3 pre-embedded pad 7 is accurately positioned, the grouting pipe 11 on the pad 7 is connected to the bottom of the smooth plastic pipe 9, and the grout return and venting pipe 12 is connected to the top of the inside of the smooth plastic pipe 9; pour the reinforced concrete base 13 concrete, and the reinforced concrete base 13 must be tightly attached to the slope 2 of the foundation pit.

[0034] S14: Anchor head 1-3 anchor bolt tensioning and temporary anchoring. After the anchor body and reinforced concrete base 13 meet the strength requirements, anchor head 1-3 anchor bolt tensioning is carried out and temporarily locked with anchor 8; during construction, the anchor bolt and anchor 8 should be protected and the anchor bolt stress should be monitored. If any loss occurs, re-tensioning should be carried out in time.

[0035] The specific construction method for S2 includes the following steps:

[0036] S21: Reinforcement construction of lining structure 3. Complete the reinforcement binding of lining structure 3 according to the design drawings.

[0037] S22: Construction of anchor bolts 1-4 in free section 2. Connect the connector 6 to the end rod 5 of anchor head 1-3, install the pad 7 of anchor head 2-5, connect the grouting pipe 11 and install the corrugated steel pipe 10. Seal both ends of the corrugated steel pipe 10 with the pad 7, and ensure that the grout return and exhaust pipe 12 on the pad of anchor head 2-5 is connected to the top of the inside of the corrugated steel pipe 10.

[0038] S23: Concrete construction of lining structure 3. After the concealed works of reinforcing steel and anchor bolts have passed the acceptance inspection, the formwork is erected and the concrete of lining structure 3 is poured.

[0039] S24: Construction of Concrete Filling 4. After the concrete strength of the lining structure 3 meets the requirements, pre-tension the anchor rods 1-5 of anchor head 2 and temporarily lock them with the anchor 8 on anchor head 2. Start filling the concrete behind the wall and observe the horizontal displacement of the lining structure 3, and adjust the pre-tension of the anchor rods in a timely manner.

[0040] S25: Anchor head 2, anchor rods 1-5 are tensioned, anchored, and grouted. After the strength of the filling concrete 4 meets the requirements, anchor head 2, anchor rods 1-5 are tensioned and anchored; cement grout is injected through anchor head 2 grouting pipe 11 until the grout concentration at the anchor head 2 return vent pipe 12 is the same as the grout concentration injected.

[0041] S26: Anchor head 2, anchor bolt 1-5 is sealed. The outer anchor head of lining structure 3 is sealed with concrete anchor body 14.

[0042] In steps S1 and S2, the excavation of the foundation pit and the prestressed anchor structure 1 are constructed in layers from top to bottom, while the lining structure 3 and the anchor extension are constructed in layers from bottom to top, thus reducing the construction difficulty and safety risks.

[0043] The free section 1-2 is sealed with a smooth plastic pipe 9 and isolated from the anchoring section 1-1. Grouting is carried out at the bottom of the hole in time before the concrete construction of the reinforced concrete base 13. The outer sides of the anchoring section 1-1 and the free section 1-2 are filled with grout to reduce the problems of rock mass fracture and hole collapse and slope disturbance.

[0044] After the prestressing of anchor head 1-3 is tensioned, it is temporarily anchored without grouting. When tensioning free section 1-4, the total length of the free section is ensured to be not less than 5m, thus reducing the prestress loss during the tensioning of anchor head 1-5.

[0045] After the anchor head 1-5 is prestressed and anchored, the free section 1-2 and the free section 2-4 are grouted together. The smooth plastic pipe 9 of the free section 1-2 and the corrugated steel pipe 10 of the free section 2-4 are connected and connected through the grouting pipe 11 and the grout return and exhaust pipe 12 to ensure that the grouting is full and dense.

[0046] The free section 2 1-4 is sealed with corrugated steel pipe 10, which has a strong grip with concrete and ensures that the anchor structure 1 is integrated with the concrete into a complete whole.

[0047] The filling concrete 4 is constructed in layers along with the lining structure 3. The stability and safety of the lining structure 3 are ensured by pre-tensioning and timely adjustment of the pre-tension force.

[0048] The described structure and its construction method are applicable to the design of prestressed anchored lining wall structures to achieve a permanent and temporary reinforcement effect of foundation pit slope support and lining wall anchoring. To reduce the amount of concrete filling behind the lining wall, the slope of the foundation pit should ideally be 65° or higher, the rock mass should be relatively fractured, and the surrounding rock integrity coefficient Kv value should be greater than 0.35.

[0049] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. A permanent and temporary combined prestressed anchor structure, characterized in that, It includes a multi-segment anchor structure, which, from bottom to top, consists of an anchoring segment, a free segment one, an anchor head one, a free segment two, and an anchor head two; The anchoring section is an anchor body used to transfer the tensile force of the slope support and lining structure to the surrounding strata. The anchor body is formed by bonding the anchor rod body to the soil and rock with cement grout or cement mortar. The free section one includes an anchor rod body located between the anchoring section and the anchor head one. The outer side of the anchor rod body is fitted with a smooth round plastic tube that is sealed to the anchoring section, and the upper end is connected to the anchor rod body of the free section two through a connector. The anchor head is used to transfer the tension from the anchor body to the foundation pit slope, and includes a reinforced concrete base, a pad plate and an anchor. The reinforced concrete base is connected to the slope mesh spraying or protective net to form a temporary support structure for the foundation pit slope. The pad plate is connected to a grouting pipe and a grout return and venting pipe. The grouting pipe is connected to the bottom of the smooth plastic pipe and the grout return and venting pipe is connected to the top of the inside of the smooth plastic pipe. The second free section includes an anchor body located between the first anchor head and the second anchor head. A corrugated steel pipe is sleeved on the outside of the anchor body. Both ends of the corrugated steel pipe are sealed to the pads of the two anchor heads. The lower end of the anchor body is connected to the anchor body of the first free section through a connector. The second anchor head is used to transfer tension from the rod body to the lining structure. It includes a pad plate, an anchor, and a sealing anchor body. The pad plate is embedded in the lining structure. A grouting pipe and a grout return and venting pipe are connected to the pad plate. The grouting pipe is connected to the bottom of the corrugated steel pipe and is connected and communicates with the grouting pipe on the pad plate of the first anchor head. The grout return and venting pipe is connected to the top of the inside of the corrugated steel pipe. The sealing anchor body is integrated with the lining structure to seal the anchor.

2. The permanent and temporary combined prestressed anchor structure according to claim 1, characterized in that, The smooth plastic tube and the anchoring section are sealed by wrapping an outer layer of engineering tape.

3. The permanent and temporary combined prestressed anchor structure according to claim 1, characterized in that, The length of the first free segment is not less than 5m.

4. The permanent and temporary combined prestressed anchor structure according to claim 1, characterized in that, The length of the second free section is determined based on the anchor structure location, slope angle, and lining thickness, and its total length with the first free section accounts for 1 / 3 to 1 / 2 of the total length of the anchor body.

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