WO2019119900A1 - 一种降低预应力损失的低张拉锚索施工方法 - Google Patents

一种降低预应力损失的低张拉锚索施工方法 Download PDF

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WO2019119900A1
WO2019119900A1 PCT/CN2018/105355 CN2018105355W WO2019119900A1 WO 2019119900 A1 WO2019119900 A1 WO 2019119900A1 CN 2018105355 W CN2018105355 W CN 2018105355W WO 2019119900 A1 WO2019119900 A1 WO 2019119900A1
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anchoring agent
anchor cable
slow
ultra
anchoring
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PCT/CN2018/105355
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English (en)
French (fr)
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张农
谢正正
袁钰鑫
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中国矿业大学
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D20/00—Setting anchoring-bolts
    • E21D20/003—Machines for drilling anchor holes and setting anchor bolts
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D20/00—Setting anchoring-bolts
    • E21D20/02—Setting anchoring-bolts with provisions for grouting

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  • the invention relates to a prestressed anchor cable construction technology, in particular to a low tension anchor cable construction method suitable for mine and geotechnical engineering to reduce prestress loss.
  • anchor cables are often used instead of traditional anchors for construction.
  • the anchor cable has flexibility and flexibility, and the length is not limited by the construction space.
  • the strength is much higher than the strength of the bolt and can withstand more load.
  • the tensioning jack and the clip-type lock can be used to apply a larger preload. Stress and other advantages.
  • the anchor cable is widely used.
  • the anchor cable Due to the prestressing of the anchor cable using the tension jack and the clip anchor, it is inevitable that the anchor cable will be retracted due to the retraction of the clip in the anchor, resulting in prestress loss; at the same time, in order to ensure high anchoring force, the anchor length Often more than 2m, the free section of the anchor cable is shorter, the elongation is small, and the prestress loss caused by the cable retraction is huge, up to 40%-50%; the front end of the anchoring section will also be prestressed due to slip debonding. loss.
  • the prior art generally uses a super-tensioning method, that is, by increasing the tensile force to offset the loss, the residual stress after the jack is unloaded can meet the design requirements.
  • this method needs to apply nearly 2 times of design pre-tightening force when tensioning, the tensioning machine will be reduced in life due to high load operation, and the cable strand strands will be damaged or even broken due to high pre-tension, construction time and The difficulty will also rise.
  • the object of the present invention is to overcome the deficiencies in the prior art and to provide a low tension cable construction method for reducing prestress loss.
  • the low tension cable construction method for reducing prestress loss of the present invention has the following steps:
  • the slow anchoring agent is inserted into the drilling hole in the following sequence, and the ultra-fast anchoring agent and the slow anchoring agent are pushed into the drilling hole by the anchor cable, and the anchor cable will be ultra-fast anchoring agent.
  • the slow anchoring agent is inserted into the bottom end of the borehole to puncture the ultra-fast anchoring agent and the slow anchoring agent, and the anchor cable is used to break up the package of the ultra-fast anchoring agent and the slow anchoring agent and stir, wherein the ultra-fast anchoring agent and There is a very small section near the interface of the slow anchoring agent that produces mixing but does not affect the actual effect, and the anchor cable is allowed to stand, so that the ultra-fast anchoring agent is completely cured;
  • the ultra-fast anchoring agent size only needs to meet the design pre-tightening force requirement.
  • the slow anchoring agent size satisfies the anchoring force generated by the two anchoring agents in accordance with the design drawing force requirement.
  • the ultra-fast anchoring agent length is often 1/5 of the length of the anchor cable.
  • the length of the slow anchoring agent is 1/5-3/5 of the anchor rod body.
  • the tensioning and holding process is completed before the slow anchoring agent begins to solidify, with a time of 30 s to 1 min.
  • the slow anchoring agent begins to cure much longer than the ultrafast anchoring agent ultrafast anchoring agent model Cka, gel time 8-25s, slow anchoring agent model M, gel time >180s.
  • the standard tensile load is the sum of the design preload and the cable retraction loss force.
  • the present invention Since the above technical solution is adopted, the present invention has the following advantages compared with the prior art:
  • the additional tensile force required during the super-tensioning process is much smaller than the traditional construction method.
  • the tension of the tensioning jack is small, the tension time is shortened, the mechanical service life is prolonged, and the anchor cable is less stressed during tensioning. The strands are not easily broken.
  • the non-anchoring section of the anchor cable is the longest in the tensioning process of the present invention, and the anchor cable is extended longer under the same prestressing condition, and the tensioning jack is unloaded.
  • the prestress loss due to the cable retraction after pressing is smaller.
  • FIG. 1 is a schematic view showing a construction method of a low tension anchor cable of the present invention.
  • the method for constructing a low tension anchor cable for reducing prestress loss of the present invention has the following steps:
  • the slow anchoring agent 2 is inserted into the drilling hole in the following order, the slow curing agent 2 starts to cure much longer than the ultra-fast anchoring agent 1 ultra-fast anchoring agent 1
  • the gel time is 8-25s
  • the slow anchoring agent 2 is M
  • the gel time is >180s
  • the ultra-fast anchoring agent 1 size only needs to meet the design pre-tightening force requirement
  • the slow anchoring agent 2 size meets two
  • the anchoring force jointly produced by the anchoring agent meets the design drawing force requirement.
  • the length of the ultra-fast anchoring agent 1 is usually 1/5 of the length of the anchor cable
  • the length of the slow anchoring agent 2 is 1/5-3/5 of the length of the anchor cable 3.
  • the anchor cable 3 is used to push the ultra-fast anchoring agent 1 and the slow anchoring agent 2 into the borehole, and the anchor cable 3 pushes the ultra-fast anchoring agent 1 and the slow anchoring agent 2 into the bottom end of the drill hole to puncture the ultra-fast anchoring.
  • the agent 1 and the slow anchoring agent 2 the package of the ultra-fast anchoring agent 1 and the slow anchoring agent 2 is pulverized by the anchor cable 3 and stirred, and there is a vicinity of the interface between the ultra-fast anchoring agent 1 and the slow-speed anchoring agent 2 A very small section produces mixing but does not affect the actual effect, and the anchor cable 3 is allowed to stand, so that the ultra-fast anchoring agent 1 is completely cured;
  • the clip anchor 4 installs the clip anchor 4 on the part outside the bore of the anchor cable 3 against the wall of the roadway, and use the tension jack to match the clip anchor 4 to tension the anchor cable 3 and maintain the standard tension.
  • the standard tensile load is the sum of the design preload and the retraction force of the anchor cable 3, at which time the ultra-fast anchoring agent 1 solidifies and anchors the top end of the anchor cable 3 to the borehole wall, tensioning and protecting
  • the loading process is completed before the slow anchoring agent 2 starts to solidify, and the wrapping time is 30s-1min.

Abstract

一种降低预应力损失的低张拉锚索施工方法，利用锚索（3）将锚固剂按照超快锚固剂（1）在前，慢速锚固剂（2）在后的顺序完全顶入钻孔中，充分搅拌，静置待超快锚固剂（1）完全固化后，利用张拉千斤顶和锚具进行张拉，并保载一段时间，张拉完成。该过程在慢速锚固剂（2）尚未开始固化前完成。在张拉过程锚索（3）自由段最长，锚具的夹片回缩引起的预应力损失比例最小；保载可消除因锚固体前端脱黏滑移引起的预应力损失。

Description

一种降低预应力损失的低张拉锚索施工方法 技术领域
本发明涉及预应力锚索施工技术，尤其是一种适应于矿山和岩土工程的降低预应力损失的低张拉锚索施工方法。
背景技术
在基础设施建设时，常常使用锚索代替传统的锚杆进行施工。相比传统的锚杆，锚索具有柔性可弯曲、长度不受施工空间的限制，强度远高于锚杆强度、可承受更大载荷，利用张拉千斤顶和夹片式锁具可施加更大预应力等优点。使得锚索得到广泛应用。
由于锚索使用张拉千斤顶和夹片式锚具施加预应力，不可避免的会发生因锚具中夹片回缩引起锚索回缩，造成预应力损失；同时为了保证高锚固力，锚固长度往往超过2m，锚索自由段较短，伸长量较小，造成锚索回缩引起的预应力损失巨大，最多达到40％-50％；锚固段前端也会因滑移脱黏造成预应力损失。
现有技术一般使用超张拉的方式，即通过提高张拉力抵消损失，使得千斤顶卸载后的残余应力能够满足设计要求。但是这种方法在张拉时需要施加近2倍的设计预紧力，张拉机具会因高负荷运转而寿命骤减，锚索钢绞线股会因高预拉力损伤甚至断裂，施工时间和难度也均会上升。目前尚缺少一种可降低张拉过程中预应力损失的锚索施工方法。
发明内容
技术问题：本发明的目的是克服已有技术中的不足，提供一种降低预应力损失的低张拉锚索施工方法。
技术方案：本发明的降低预应力损失的低张拉锚索施工方法，其步骤如下：
a.按照锚索的尺寸在巷道壁上进行钻孔；
b.按照超快锚固剂在前，慢速锚固剂在后的顺序塞入钻孔，并使用锚索将超快锚固剂和慢速锚固剂顶入钻孔，待锚索将超快锚固剂和慢速锚固剂顶入钻孔底端后戳破超快锚固剂和慢速锚固剂，利用锚索搅碎超快锚固剂和慢速锚固剂的包装并进行搅拌，其中超快锚固剂和慢速锚固剂的交界面附近会有极小一段产生混合但是不影响实际效果，静置锚索，使超快锚固剂完全固化；
c.在锚索钻孔外的部分安装夹片式锚具抵住巷道壁，使用张拉千斤顶配合夹片式锚具对锚索进行张拉预紧并维持标准张拉力进行保载，此时超快锚固剂凝固并将锚索顶端部分与钻孔壁锚固，张拉时超快锚固剂凝固部分外侧与钻孔壁逐渐被拉开，而此时慢速锚固剂还未凝 固仍为流态，成为脱黏滑移，造成锚索松弛预紧力损失；
e.控制千斤顶卸压，结束保载过程，完成锚索的安装，等待慢速锚固剂固化，完成锚索的施工。
超快锚固剂尺寸仅需满足设计预紧力要求，慢速锚固剂尺寸满足两节锚固剂共同产生的锚固力符合设计拉拔力要求，超快锚固剂长度常为锚索长度的1/5，慢速锚固剂长度为锚索杆体的1/5-3/5)。
所述张拉和保载过程在慢速锚固剂开始固化前完成，其中包在时间为30s-1min。
所述的慢速锚固剂的开始固化时间远大于超快锚固剂超快锚固剂型号为Cka，凝胶时间为8-25s,慢速锚固剂型号为M，凝胶时间为>180s。
所述的标准张拉力载荷为设计预紧力与锚索回缩损失力的总和
有益效果：由于采用了上述技术方案，本发明与现有技术相比具有如下优点：
(1)超张拉过程中需额外施加的张拉力远小于传统施工法，张拉千斤顶具需承受的载荷小，张拉时间缩短，机械使用寿命延长，锚索在张拉期间受力较小，钢绞线股不易断裂。
(2)同树脂锚固剂完全固化再张拉的施工方法相比，本发明的张拉过程中锚索非锚固段最长，锚索在同等预应力条件下沿伸更长，张拉千斤顶卸压后因锚索回缩产生的预应力损失更小。
(3)张拉过程中保载一段时间后再卸除千斤顶，可消除因锚固段前端脱黏滑移造成的预应力损失。
(4)慢速树脂锚固剂在锚索处于预应力状态下固化，相当于预应力锚固，更有利于稳固煤岩体。
附图说明
图1是本发明的低张拉锚索施工方法示意图。
图中：1-超快锚固剂，2-慢速锚固剂，3-锚索，4-夹片式锚具。
具体实施方式
下面结合附图对本发明的一个实施例作进一步的描述：
如图1所示，本发明的降低预应力损失的低张拉锚索施工方法，其步骤如下：
a.按照锚索3的尺寸在巷道壁上进行钻孔；
b.按照超快锚固剂1在前，慢速锚固剂2在后的顺序塞入钻孔，所述的慢速锚固剂2的开始固化时间远大于超快锚固剂1超快锚固剂1型号为Cka，凝胶时间为8-25s,慢速锚固剂 2型号为M，凝胶时间为>180s，超快锚固剂1尺寸仅需满足设计预紧力要求，慢速锚固剂2尺寸满足两节锚固剂共同产生的锚固力符合设计拉拔力要求，超快锚固剂1长度常为锚索长度的1/5，慢速锚固剂2长度为锚索3杆体的1/5-3/5，使用锚索3将超快锚固剂1和慢速锚固剂2顶入钻孔，待锚索3将超快锚固剂1和慢速锚固剂2顶入钻孔底端后戳破超快锚固剂1和慢速锚固剂2，利用锚索3搅碎超快锚固剂1和慢速锚固剂2的包装并进行搅拌，其中超快锚固剂1和慢速锚固剂2的交界面附近会有极小一段产生混合但是不影响实际效果，静置锚索3，使超快锚固剂1完全固化；
c.在锚索3钻孔外的部分安装夹片式锚具4抵住巷道壁，使用张拉千斤顶配合夹片式锚具4对锚索3进行张拉预紧并维持标准张拉力进行保载，所述的标准张拉力载荷为设计预紧力与锚索3回缩损失力的总和，此时超快锚固剂1凝固并将锚索3顶端部分与钻孔壁锚固，张拉和保载过程在慢速锚固剂2开始固化前完成，其中包在时间为30s-1min，张拉时超快锚固剂1凝固部分外侧与钻孔壁逐渐被拉开，而此时慢速锚固剂2还未凝固仍为流态，成为脱黏滑移，造成锚索松弛预紧力损失；
e.控制千斤顶卸压，结束保载过程，完成锚索3的安装，等待慢速锚固剂2固化，完成锚索3的施工。
本发明的技术方案已由可选实施例揭示如上。本领域技术人员应当意识到在不脱离本发明所附的权利要求所揭示的本发明的范围和精神的情况下所作的更动与润饰，均属本发明的权利要求的保护范围之内。

Claims (5)

  1. 一种降低预应力损失的低张拉锚索施工方法，其特征是步骤如下：
    a.按照锚索(3)的尺寸在巷道壁上进行钻孔；
    b.按照超快锚固剂(1)在前，慢速锚固剂(2)在后的顺序塞入钻孔，并使用锚索(3)将超快锚固剂(1)和慢速锚固剂(2)顶入钻孔，待锚索(3)将超快锚固剂(1)和慢速锚固剂(2)顶入钻孔底端后戳破超快锚固剂(1)和慢速锚固剂(2)，利用锚索(3)搅碎超快锚固剂(1)和慢速锚固剂(2)的包装并进行搅拌，其中超快锚固剂(1)和慢速锚固剂(2)的交界面附近会有极小一段产生混合但是不影响实际效果，静置锚索(3)，使超快锚固剂(1)完全固化；
    c.在锚索(3)钻孔外的部分安装夹片式锚具(4)抵住巷道壁，使用张拉千斤顶配合夹片式锚具(4)对锚索(3)进行张拉预紧并维持标准张拉力进行保载，此时超快锚固剂(1)凝固并将锚索(3)顶端部分与钻孔壁锚固，张拉时超快锚固剂(1)凝固部分外侧与钻孔壁逐渐被拉开，而此时慢速锚固剂(2)还未凝固仍为流态，成为脱黏滑移，造成锚索松弛预紧力损失；
    e.控制千斤顶卸压，结束保载过程，完成锚索(3)的安装，等待慢速锚固剂(2)固化，完成锚索(3)的施工。
  2. 根据权利要求1所述的降低预应力损失的低张拉锚索施工方法，其特征是：所述的超快锚固剂(1)尺寸仅需满足设计预紧力要求，慢速锚固剂(2)尺寸满足两节锚固剂共同产生的锚固力符合设计拉拔力要求，超快锚固剂(1)长度常为锚索长度的1/5，慢速锚固剂(2)长度为锚索(3)杆体的1/5-3/5)。
  3. 根据权利要求1所述的降低预应力损失的低张拉锚索施工方法，其特征是：所述张拉和保载过程在慢速锚固剂(2)开始固化前完成，其中包在时间为30s-1min。
  4. 根据权利要求1所述的低张拉预应力损失的锚索施工方法，其特征是：所述的慢速锚固剂(2)的开始固化时间远大于超快锚固剂(1)超快锚固剂(1)型号为Cka，凝胶时间为8-25s,慢速锚固剂(2)型号为M，凝胶时间为>180s。
  5. 根据权利要求1所述的低张拉预应力损失的锚索施工方法，其特征是：所述的标准张拉力载荷为设计预紧力与锚索(3)回缩损失力的总和。
PCT/CN2018/105355 2017-12-18 2018-09-13 一种降低预应力损失的低张拉锚索施工方法 WO2019119900A1 (zh)

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CN114062248A (zh) * 2021-11-02 2022-02-18 西南交通大学 一种岩土锚索管道自由段摩阻值测试系统及测试方法

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CN108104852B (zh) * 2017-12-18 2019-05-14 中国矿业大学 一种降低预应力损失的低张拉锚索施工方法
CN113529705B (zh) * 2021-07-21 2022-09-02 中国矿业大学(北京) 锚杆与锚索高预应力无损施加设备及方法

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