This application is the U.S. national phase entry of PCT/CN2011/075640, with an international filing date of 13 Jun. 2011, the entire disclosure of which is fully incorporated herein by reference.
The disclosure relates to new material for monitoring and early warning the soft rock slope stableness and monitoring the activity of seismogenic fault, more particularly, to a constant-resistance and large deformation anchor cable and the constant-resistance device thereof, which belong to the area of reinforcing, monitoring and early warning the large deformation of the soft rock slope.
After the 1950s, with the improvement of pre-stress technology, the gradually perfection of anchor reinforce theory, designing method, regulations and standards, as well as the continually progress of anchor cable anti-corrosion means, a pre-stress anchor cable is progressed faster and faster. Currently, the bearing pre-stress of a single pre-stress anchor cable of rock reaches 16MN (in German). The pre-stress anchor cable is various in structures and types, and is improving and perfecting continually along with the utilization level. Pre-stress anchoring technology is widely used in various areas of rock geotechnical reinforcement engineering, and rich engineering practice experience has been accumulated.
However, in the area of monitoring and early warning soft rock slope and activity fault, it is found that using a conventional pre-stress anchor cable as a mechanical transmission device may have weak. For example, when the sliding force on the slide plane and fault plane exceeds the material strength of the anchor cable, the anchor cable may fracture, so that the mechanical signal transmission system may be broken, and the whole monitoring system may fail, as a result, it is incapable to monitor the whole landslip process continuously.
An objective of the disclosure is to provide a constant-resistance and large deformation anchor cable and the constant-resistance device thereof, to solve the problem in the conventional anchor cable that the anchor cable may fail due to only relying on the anchor cable strength when the sliding force exceeds the material strength of the pre-stress anchor cable.
To achieve the objective above, the disclosure provides a constant-resistance device of a constant-resistance and large deformation anchor cable including a sleeve and a constant-resistance body for fixedly connecting a cable, the sleeve is straight pipe structure, the constant-resistance body has frustum structure, and the diameter of a lower end face of the constant-resistance body is larger than the diameter of an upper end face of the constant-resistance body; the inner diameter of the sleeve is smaller than the diameter of the lower end face of the constant-resistance body, a cuneiform portion is disposed at a lower portion of an inner wall of the sleeve, the constant-resistance body is disposed at the cuneiform portion; the strength of the constant-resistance body is higher than the strength of the sleeve, so as to make the constant-resistance body have no deformation and make the sleeve have plastic deformation to generate constant resistance when the constant-resistance body moves in the sleeve.
According to a preferred embodiment of the constant-resistance device of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a plurality of through holes are disposed in the constant-resistance body, the through holes have frustum structure, and the axes of the through holes are parallel with the axis of the constant-resistance body.
To achieve the objective above, the disclosure provides a constant-resistance and large deformation anchor cable including cables, an anchoring device, a loading plate and clamping sheets, upper ends of the cables being fixed to the anchoring device and the loading plate via the clamping sheets, wherein the constant-resistance and large deformation anchor cable further includes a constant-resistance device, the constant-resistance device includes a sleeve and a constant-resistance body, the sleeve has a straight pipe structure, and the constant-resistance body has a frustum structure, the diameter of a lower end face of the constant-resistance body is larger than the diameter of the upper end face of the constant-resistance body; the inner diameter of the sleeve is smaller than the diameter of the lower end face of the constant-resistance body, a cuneiform portion is disposed at a lower portion of the inner wall of the sleeve, the constant-resistance body is disposed at the cuneiform portion; the strength of the constant-resistance body is higher than the strength of the sleeve, so as to make the constant-resistance body have no deformation and make the sleeve have plastic deformation to generate constant resistance when the constant-resistance body moves in the sleeve; lower ends of the cables are fixed to the constant-resistance body.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, the constant-resistance body comprises a plurality of through holes, the through holes have frustum structures, and the axes of the through holes are parallel with the axis of the constant-resistance body; the lower ends of the cables are fixed in the through hole via the clamping sheets.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a skid-resistance baffle is fixed to the upper end of the sleeve, and the cables pass through the skid-resistance baffle.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a partition board is fixed to an upper portion of the inner wall of the sleeve, the cables pass through the partition board, and water-proof and anti-corrosion material is filled in the sleeve above the partition board.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a baffle covers the lower end face of the constant-resistance body to prevent the clamping sheets in the through hole from falling off.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a plurality of first type holes are disposed at the baffle, the lower end of the cables pass the first type holes on the baffle.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a sealing guiding head is disposed at the lower end of the sleeve.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a second type hole is disposed at the center of the baffle, a screw passes through the second type hole to fix the baffle to the lower end face of the constant-resistance body.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, a mechanical sensor is disposed at the upper ends of the cables to detect the force condition of the cables, and the mechanical sensor is disposed between the anchoring device and the loading plate.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, the upper end face of the guiding head comprises a recess.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, the water-proof and anti-corrosion material is mixed material of paraffin, asphalt and grease.
According to a preferred embodiment of the constant-resistance and large deformation anchor cable in an embodiment of the disclosure, the front end of the guiding head has a shape of cone or frustum with a flat head.
In the constant-resistance and large deformation anchor cable adapted to monitoring soft rock slope and seismogenic fault activity, seen from the landslip disaster monitoring and seismogenic fault activity monitoring, the anchor cable does not fracture or lose the monitoring effect due to the sliding force being higher than the ultimate strength of the anchor cable during the rock slide process. Instead, the constant-resistance body slides in the sleeve to resist the fracture of the remained sliding force. The device has rational construction, is convenient in usage, has the mechanical characteristic of both resisting performance and sliding performance, and has constant resistance to prevent fracture, which may monitor and early warn the whole process of the landslip hazard and the seismogenic fault activity.
Hereinafter, the embodiments are described along with the accompanying drawing.
In view of the drawback and problem of the conventional technology, based on the control theory of constant-resistance and large deformation and basic theory of anchoring system, the disclosure discloses a constant-resistance and large deformation anchor cable which is used in reinforcing, monitoring, early warning of soft rock slope and seismogenic fault, when the load applied on the anchor cable exceeds a designed threshold value, the constant-resistance device disposed at the lower end of the anchor cable and formed by the constant-resistance body and the sleeve may resist the fracture generated by the remaining load by sliding the constant-resistance body in the sleeve.
As shown in
To fasten the cables 7 to the constant-resistance body 5 conveniently and efficiently, the constant-resistance body 5 in the preferred embodiment includes a plurality of through holes 500 to allow a plurality of cables 7 to pass through and to accommodate the clamping sheets 4. As shown in
To prevent the constant-resistance body 5 from sliding out of the sleeve 8 due to material defect or manufacturing defect, or the constant-resistance body 5 slides out of the sleeve 8 normally, a skid-resistance baffle 11 is fixed to an upper end of the sleeve 8 by means of welding, for example. The skid-resistance baffle 11 is provided with holes for passing the cables. Preferably, the axes of the holes and the axes of the through holes 500 of the constant-resistance body 5 are in the same line.
Before applying the anchor cable to the soft rock in the application field, the cables 7 is fixed to the lower ends of the through holes 500 of the constant-resistance body 5 via the clamping sheets 4. During applying the anchor cable, the cables 7 may have forth-and-back slide to make the clamping sheets 4 fall off. To prevent the falling off of the clamping sheets 4, as shown in
To prevent slurry or underground water from entering the sleeve 8 and corrode the inner wall of the constant-resistance body 5 and the sleeve 8 which may cause unable to achieve the constant-resistance during fixing the constant-resistance and large deformation anchor cable, a partition board 9 is fixed in the inner wall of the sleeve 8 in the preferred embodiment. As shown in
To prevent corrosion of the sleeve 8 and the constant-resistance body 5, the lower end of the sleeve 8 in the embodiment is provided with a sealing guiding head 1. Preferably, the front end of the guiding head 1 is cone-shaped, and it may also be a frustum with flat head. A recess is disposed at the upper end, and the cone structure is benefit for reducing resistance during applying anchoring device. The recess may be used to reduce weight, simplify structure and accommodate the cables 7 extending out of the baffle 2.
To obtain the tensile force of the cables 7, a mechanical sensor (not shown in the drawings) is disposed between the loading plate 12 and the anchoring device 13 at the upper ends of the cables 7.
As shown in
When the larger deformation of the rock-soil mass is generated, the deformation energy may be applied to the cables 7 to turn to the axial tensile force of the cables 7. When the axial tensile force is less than the cable designed constant resistance, due to the friction force, no displacement is generated between the constant-resistance body 5 and the sleeve 8. The force sensed by the mechanical sensor is an axial tensile force on the cables 7 in its elastic range. When the axial tensile force of the cable 7 is higher than or equal to the design constant resistance of the cable 7, the constant-resistance body 5 begins to slide long the sleeve 8, and the force sensed by the mechanical sensor is mainly the constant resistance. Since the constant resistance is a friction resistance between the sleeve 8 and the constant-resistance body 5, during sliding process, under the condition that the inner defect of the sleeve 8 is not considered, the constant resistance is stable, the mechanical information sensed by the mechanical sensor is stable too. The collected data can be drawn as the tensile force-displacement curve in
To sum up, by utilizing the disclosure, when the sliding rock turns from a stable state to a non-stable state, from a near-sliding state to a critical sliding state, the sliding force applied to the rock increases continuously. When the sliding force exceeds the designed constant resistance, the constant-resistance body slides to resist the fracture of the anchor cable generated by the large deformation of the rock-soil mass. Seen from the landslip disaster monitoring and seismogenic fault activity monitoring, the anchor cable does not fracture or lose the monitoring effect due to the sliding force being higher than the ultimate strength of the anchor cable during the rock slide process. Instead, the constant-resistance body slides in the sleeve to resist the fracture of the remained sliding force. The device has rational construction is convenient in usage, has the mechanical characteristic of both resisting performance and sliding performance, and has constant resistance to prevent fracture, which may monitor and early warn the whole process of the landslip hazard and the seismogenic fault activity.
Although the disclosure has been described as above in reference to several typical embodiments, it is to be understood that the terms used therein are just illustrative and exemplary rather than restrictive. Since the disclosure can be applied in various forms without departing from the spirit or principle of the disclosure, it is to be understood that the abovementioned embodiments will not be limited to any specific details mentioned above, rather, they should be construed broadly in the spirit or concept of the disclosure defined by the appended claims. Therefore, the present disclosure aims to cover all the modifications or variations falling within the protection scope defined by the appended claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CN2011/075640 | 6/13/2011 | WO | 00 | 4/17/2014 |
Publishing Document | Publishing Date | Country | Kind |
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WO2012/171155 | 12/20/2012 | WO | A |
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