Inhaul cable prestress tensioning and locking method

Abstract

The invention relates to the field of geological disaster prevention and control, and discloses an inhaul cable prestress tensioning and locking method which comprises the following steps that firstly, an inhaul cable and a force transmission mechanism are prepared, and the inhaul cable comprises a tensioning end and an anchoring end; secondly, the anchoring end of the inhaul cable is anchored to the side slope on one side of the dangerous rock, a notch groove is formed in the other side of the dangerous rock, and a force transmission mechanism is arranged in the notch groove; thirdly, the inhaul cable is bound to the dangerous rock, the tensioning end of the inhaul cable penetrates through the force transmission mechanism and then is away from the slope, and therefore the tensioning direction is changed; and fourthly, the inhaul cable is tensioned, the force transmission mechanism comprises an anchoring unit, and the tensioning end of the tensioning end is fixed to the anchoring unit. The purpose of applying and locking the high prestress of the transversely or approximately horizontally arranged dangerous rock binding steel strand is effectively achieved.

Description

Technical Field

[0001] The present invention relates to the field of geological disaster prevention and control, and in particular to a cable prestressing and locking method. Background Art

[0002] In the field of dangerous rock mass prevention and control, a commonly used technical method currently is to use steel strands to tie and reinforce unstable dangerous rock masses, similar to "tying a belt" on the dangerous rock mass. Specifically, the steel strands are wrapped around the dangerous rock mass and anchored to the stable bedrock cliffs on both sides of the dangerous rock mass. The purpose is to enhance the overall stability of the dangerous rock mass through the restraining effect of the steel strands.

[0003] However, existing engineering practices have significant technical bottlenecks and limitations: 1. Primitive and ineffective prestressing methods: The project relied solely on manual pulling of the steel strands to achieve initial tension. This manual operation applied an extremely weak effective prestress, typically less than 0.5 kN. This minimal prestress meant the strands provided virtually no active support for the dangerous rock mass, acting more like a passive, inefficient binding constraint.

[0004] 2. Traditional tensioning technology is unsuitable: Because the binding strands are typically laid horizontally and parallel to the surface of the dangerous rock mass, this creates a fundamental technical obstacle: the inability to provide the necessary, stable support points for the core equipment (such as tensioning jacks) that applies high prestress. The design principles and operating procedures of existing, mature and widely used anchor cable (steel strand) prestressing and locking technologies are based on the principle that the anchor cable strands are perpendicular (or nearly perpendicular) to the slope surface or the surface of the dangerous rock mass.

[0005] 3. Technical gap in transverse prestressing of steel strands: Due to the contradiction between the above-mentioned layout form and support conditions, the industry currently lacks mature and effective technical methods and special equipment that can implement effective and controllable high-prestressing tensioning and achieve reliable locking of transverse or nearly horizontal steel strands used to bind dangerous rock masses.

[0006] In summary, developing a method and device that can overcome the existing technical bottlenecks and effectively solve the problem of high prestressing and locking of dangerous rock binding steel strands arranged horizontally or nearly horizontally has become an urgent technical need to improve the effectiveness of dangerous rock prevention and control projects and ensure project safety. Summary of the Invention

[0007] The present invention aims to provide a cable prestressing and locking method, which effectively solves the problem of high prestressing and locking of dangerous rock binding steel strands arranged horizontally or nearly horizontally.

[0008] To achieve the above object, the present invention adopts the following technical solution: a cable prestressing and locking method, comprising the following steps: Step 1: Prepare the cable and force transmission mechanism. The cable includes a tensioning end and an anchoring end. Step 2: Anchor the anchor end of the cable on the slope on one side of the dangerous rock, set a groove on the other side of the dangerous rock, and set the force transmission mechanism in the groove; Step 3: Tie the cable to the dangerous rock, pass the tensioning end of the cable through the force transmission mechanism and away from the slope, thereby changing the tensioning direction; Step 4: tension the cable. The force transmission mechanism includes an anchoring unit, and the tensioning end of the pulling end is fixed on the anchoring unit.

[0009] The beneficial effects of this program are: The present invention provides a practical method for prestressing and locking steel strands when the steel strands are parallel to the surface of the dangerous rock mass or the slope surface, so as to effectively solve the problem of high prestressing and locking of dangerous rock-binding steel strands arranged horizontally or nearly horizontally.

[0010] Specifically, the direction of the cable is changed by the force transmission mechanism, so that the prestressed direction of the steel strand parallel to the surface of the dangerous rock mass or the slope is changed from pointing inside the slope to pointing outside the slope, that is, the cable points outside the slope after passing through the force transmission mechanism, so that the tensioning equipment can be supported on the force transmission mechanism and tension the tensioning end of the cable. This method can achieve prestressed tensioning of more than 100KN, and the steel strand is transformed from a passive support structure to an active support structure, thereby achieving an active support effect on the dangerous rock mass.

[0011] Furthermore, the force transmission mechanism includes a force transmission unit, and the force transmission unit includes an anchor cable and a rotating part.

[0012] In step three, an anchor hole is set at the bottom of the groove, and the anchor cable is anchored in the anchor hole. The part of the anchor cable away from the anchor hole is rotatably connected to the rotating member; the tensioning end of the cable passes around the rotating member to change the tensioning direction.

[0013] Furthermore, the force transmission unit also includes a U-shaped steel sleeve, and the rotating member is a bearing; In step three, the steel sleeve passes through the bearing, the anchor cable passes through the steel sleeve, and both ends of the anchor cable are anchored in the anchor hole.

[0014] Furthermore, in step three, after the force transmission unit is installed, a support unit is installed in the groove. The support unit includes an inlet pipe, an outlet pipe, a bottom mold, and a top mold. The inlet pipe and the outlet pipe both pass through the bottom mold and the top mold. The cable is passed through the inlet pipe and around the rotating part, and then the cable is passed through the outlet pipe. The bottom mold and the top mold are fixed. The bottom mold and the groove cooperate to surround the force transmission unit. Concrete is poured between the bottom mold, the top mold, and the groove to form a support portion. In step 4, the anchoring unit is supported on the support portion.

[0015] Furthermore, the method further includes step five: pouring concrete in the groove to form an anchor sealing portion, wherein the anchor sealing portion covers the anchor unit.

[0016] Furthermore, the groove is a V-shaped groove.

[0017] Furthermore, the calculation formula for the groove depth H is: H=H1+H2+H3; H1-reserved bearing rotation space, H1=rotating part radius + (10-20) cm; H2-support unit thickness, calculated based on the force on the support unit to ensure that the support unit has sufficient rigidity and strength; H3-The thickness of the anchor seal to ensure coverage of the anchor unit.

[0018] Furthermore, the calculation formula for the groove width B is: B=B1+B2; B1=(H×L1) / (H+L2); B2-Width required for installation of anchoring unit; L1-The part of the cable between the bearing and the dangerous rock is the tight section, and the projection of the tight section in the width direction of the V-groove is L1; L2-The projection of the part of the tension section outside the V-groove in the depth direction of the V-groove is L2.

[0019] Furthermore, the anchoring unit includes, from the inside to the outside, a first pad, a strain gauge, a second pad and an anchor.

[0020] This solution also has the following effects: 1. By driving the anchor cable into the slope, the force transmission unit and the slope are firmly connected. By setting a rotating part so that the cable can pass around the rotating part, the tensioning direction of the cable is changed, so that the slope can provide a reaction force for the tensioning device.

[0021] 2. To prevent the cable from rubbing against the anchor cable during tensioning, which can cause wear and increase stress, this solution installs a steel sleeve between the rotating part and the anchor cable. The steel sleeve is more rigid than the anchor cable, and the U-shaped structure of the steel sleeve is used to maintain a distance between the anchor cable at the end of the steel sleeve and the cable in the middle of the steel sleeve, thus preventing wear.

[0022] 3. By setting a V-shaped groove on the slope and using the inclined side walls of the V-shaped groove to provide supporting force for the support unit, the support unit transmits the force of the tensioning equipment to the side walls of the V-shaped groove, protecting the force transmission unit, thereby avoiding the force of the tensioning equipment from being transmitted to the force transmission unit, and further avoiding the effect of damaging the force transmission unit and changing the force direction, so as to ensure the tensioning of the cable.

[0023] 4. The V-shaped groove is divided into two parts, B1 and B2, according to the width. The B1 part mainly considers the width required for the cable to pass through the V-shaped groove. The B1 part determines the center point position of the V-shaped groove and the shape of the dangerous rock. The B2 part mainly considers the width required for the cable to pass through the V-shaped groove. At the same time, the anchor unit is also set within the B2 width range to avoid affecting the cable passing through the power transmission mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of an embodiment; Figure 2 This is a three-dimensional diagram after the embodiment is completed; Figure 3 for Figure 2 AA section view; Figure 4 for Figure 3 Magnified view of the groove; Figure 5 A three-dimensional schematic diagram of the groove of the embodiment; Figure 6 3D schematic diagram of the force transmission unit of the embodiment. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementation methods: The figure marks in the drawings of the specification include: dangerous rock 1, slope 2, cable 3, anchoring end 31, tensioning end 32, groove 4, anchor cable 51, anchor hole 52, rotating part 53, steel sleeve 54, support unit 6, inlet pipe 61, outlet pipe 62, first pad 71, stress gauge 72, second pad 73, anchor 74, and anchor sealing part 8.

[0026] Example A cable prestressing and locking method, the flow chart is as follows Figure 1 As shown, the following steps are included: Step 1: Prepare the cable 3 and the force transmission mechanism. The cable 3 is a steel wire rope or steel strand, such as Figure 2 As shown, the cable 3 is used to bind the dangerous rock 1. The cable 3 includes a tensioning end 32 and an anchoring end 31. The force transmission mechanism includes a force transmission unit and an anchoring unit. The force transmission unit includes an anchor cable 51, a rotating member 53 and a U-shaped steel sleeve 54. In this embodiment, the rotating member 53 is a bearing. The rotating member 53 is sleeved outside the steel sleeve 54. The anchor cable 51 passes through the steel sleeve 54 and is rotatably connected. The anchor cable 51 is bent at the position of the steel sleeve 54. Step 2: Figure 2 As shown, the anchor end 31 of the cable 3 is anchored on the slope 2 on the right side of the dangerous rock 1, and a groove 4 is cut on the left side of the dangerous rock 1. Figure 4 、 Figure 5Drill anchor holes 52 at the bottom of the groove 4, the anchor cable 51 is anchored at both ends in the anchor hole 52, the bearing and the steel sleeve 54 remain outside the anchor hole 52; as Figure 3-Figure 6 As shown, the calculation formula for the groove 4 depth H is: H= H1+H2+H3; H1-reserved bearing rotation space, H1=rotating part 53 radius + (10-20) cm; H2-thickness of support unit 6, calculated based on the force applied to support unit 6 to ensure that support unit 6 has sufficient rigidity and strength; H3-thickness of the anchor seal 8, ensuring coverage of the anchor unit; The calculation formula for the width B of the groove 4 is: B=B1+B2; B1=(H×L1) / (H+L2); Calculate B1 according to the similar triangle theorem; B2 - The width required to install the anchor unit; B2 must ensure sufficient installation space for components such as the steel plate, anchor cable 51, strain gauge 72, and anchor 74, while also limiting the amount of work required to carve the groove 4. A larger B2 value results in more installation space for components such as the steel plate, anchor cable 51, strain gauge 72, and anchor 74, but also increases the amount of work required. The optimal L2 length is determined based on this. L1 - The portion of the cable 3 between the bearing and the dangerous rock 1 is the tension section, and the projection of the tension section in the width direction of the groove 4 is L1; L2-The projection of the part of the tension section outside the groove 4 in the depth direction of the groove 4 is L2.

[0027] The height L of the groove 4 is to ensure that there is sufficient installation space for components such as the steel plate, anchor cable 51, stress gauge 72, anchor 74, etc. The diameter of the steel plate is generally 25 to 35 cm, and the height of the groove 4 is generally 40 cm. The location of the groove 4 is determined based on the construction space requirements and the amount of work involved in the groove 4. The closer the groove 4 is to the dangerous rock 1 ( Figure 3 The larger the angle α is, the more the construction space of the groove 4 is compressed and the smaller the amount of work done by the groove 4 is. On the contrary, the farther the groove 4 is from the dangerous rock 1 ( Figure 3 The smaller the angle α is, the larger the construction space of the groove 4 is, but the larger the amount of work involved in the groove 4 is. The position of the groove 4 is determined based on the principle that the amount of work involved in the groove 4 should be minimized while ensuring the construction space requirements. Step 3: Install the support unit 6 in the groove 4. The support unit 6 includes an inlet pipe 61, an outlet pipe 62, a bottom mold, and a top mold. The inlet pipe 61 and the outlet pipe 62 both pass through the bottom mold and the top mold. Pass the cable 3 through the inlet pipe 61 and around the rotating member 53. Then pass the cable 3 through the outlet pipe 62. Tie the cable 3 to the dangerous rock 1, fix the bottom mold and the top mold. The bottom mold and the groove 4 cooperate to surround the force transmission unit. Pour concrete between the bottom mold, the top mold, and the groove 4 to form a support part. After the support part solidifies, remove the top mold. Step 4: The anchoring unit includes, from the inside to the outside, a first pad 71, a strain gauge 72, a second pad 73, and an anchor 74. The strain gauge 72 is used to detect the stress generated during the tensioning process to ensure that the stress reaches the design value. The tensioning end 32 of the cable 3 is passed through the first pad 71, the strain gauge 72, the second pad 73, and the anchor 74 in sequence, and the cable 3 is tensioned. The anchoring unit is supported on the support portion. After tensioning, the tensioning end 32 of the cable is fixed to the anchoring unit. Step 5: pour concrete in the groove 4 to form an anchor sealing portion 8 , which covers the anchor unit and fills the groove 4 .

[0028] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A cable prestressing and locking method, characterized in that , including the following steps: Step 1: Prepare the cable and force transmission mechanism. The cable includes a tensioning end and an anchoring end. Step 2: Anchor the anchor end of the cable on the slope on one side of the dangerous rock, set a groove on the other side of the dangerous rock, and set the force transmission mechanism in the groove; Step 3: Tie the cable to the dangerous rock, pass the tensioning end of the cable through the force transmission mechanism and away from the slope, thereby changing the tensioning direction; Step 4: tension the cable. The force transmission mechanism includes an anchoring unit, and the tensioning end of the pulling end is fixed on the anchoring unit.

2. A cable prestressing and locking method according to claim 1, characterized in that: The force transmission mechanism comprises a force transmission unit, and the force transmission unit comprises an anchor cable and a rotating part. In step three, an anchor hole is set at the bottom of the groove, and the anchor cable is anchored in the anchor hole. The part of the anchor cable away from the anchor hole is rotatably connected to the rotating member; the tensioning end of the cable passes around the rotating member to change the tensioning direction.

3. A cable prestressing and locking method according to claim 2, characterized in that: The force transmission unit also includes a U-shaped steel sleeve, and the rotating part is a bearing; In step three, the steel sleeve passes through the bearing, the anchor cable passes through the steel sleeve, and both ends of the anchor cable are anchored in the anchor hole.

4. A cable prestressing and locking method according to claim 2, characterized in that: In step three, after installing the force transmission unit, the support unit is installed in the groove. The support unit includes an inlet pipe, an outlet pipe, a bottom mold, and a top mold. The inlet pipe and the outlet pipe both pass through the bottom mold and the top mold. The cable is passed through the inlet pipe and around the rotating part, and then the cable is passed through the outlet pipe. The bottom mold and the top mold are fixed. The bottom mold and the groove cooperate to surround the force transmission unit. Concrete is poured between the bottom mold, the top mold, and the groove to form a support part. In step 4, the anchoring unit is supported on the support portion.

5. A cable prestressing and locking method according to claim 1, characterized in that: The method further includes step five: pouring concrete in the groove to form an anchor sealing portion, wherein the anchor sealing portion covers the anchoring unit.

6. A cable prestressing and locking method according to claim 1, characterized in that: The groove is a V-shaped groove.

7. A cable prestressing and locking method according to claim 6, characterized in that: The calculation formula for the groove depth H is: H=H1+H2+H3; H1-reserved bearing rotation space, H1=rotating part radius + (10-20) cm; H2-support unit thickness, calculated based on the force on the support unit to ensure that the support unit has sufficient rigidity and strength; H3-The thickness of the anchor seal to ensure coverage of the anchor unit.

8. A cable prestressing and locking method according to claim 7, characterized in that: The calculation formula for the groove width B is: B=B1+B2; B1=(H×L1) / (H+L2); B2-Width required for installation of anchoring unit; L1-The part of the cable between the bearing and the dangerous rock is the tight section, and the projection of the tight section in the width direction of the V-groove is L1; L2-The projection of the part of the tension section outside the V-groove in the depth direction of the V-groove is L2.

9. A cable prestressing and locking method according to claim 1, characterized in that: The anchoring unit includes a first pad, a strain gauge, a second pad and an anchor from the inside to the outside.

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