改良型锚索注浆浆液的研究和应用

Research and Application of Improved Anchor Cable Grouting Slurry

使用普通硅酸盐水泥浆液时锚索从成孔至张拉至少需要5 d时间,为了缩短该时间,本文以北京城市副中心综合管廊第4标段(一期)项目锚索注浆为例,借鉴以往砂卵石地层土体加固注浆浆液改良的思路,提出了3种方案,并最终采用由P·O 42.5普通硅酸盐水泥、硫铝酸盐水泥、饮用水组成的改良型锚索注浆浆液,通过体积比选取、浆液配合比试验、龄期试验、抗压强度试验、坍落度试验、抗拔试验,成功实现了改良型锚索注浆浆液(普通硅酸盐水泥∶硫铝酸盐水泥=1∶1)24 h强度达到设计强度75%的张拉要求(抗拔承载力20 MPa)。工程实践结果表明:改良型锚索注浆浆液的后期强度无衰退期,且经过预应力锚杆试验,锚头位移相对稳定,验收合格,大大加快了锚索张拉时间,提高了工程的施工速度,造价经济合理,为今后施工场地狭小、工期紧张的桩锚支护工程提供了参考。

In order to overcome the time limit of 5 days from drilling to tensioning of anchor cables when using ordinary Portland cement slurry,this article takes the anchor cable grouting of the Beijing urban sub-center integrated pipe corridor section 4(phase I)project as an example,draws on the ideas of improving the reinforcement grouting slurry of sand and gravel soil in the past,proposes three improvement schemes,and finally uses an improved anchor cable grouting slurry composed of P-O 42.5 ordinary Portland cement,sulfoaluminate cement,and drinking water.Through volume ratio selection,slurry mix ratio test,age test,compressive strength test,slump test,and pull-out test,the improved grouting slurry(ordinary Portland cement:sulfoaluminate cement=1:1)has been successfully achieved.The 24 hours strength meets the tensile requirement of 75%of the design strength(pull-out bearing capacityof 20 MPa).The engineering practice results show that there is no decline period in the later strength of the improved grouting slurry,and after the prestressed anchor rod test,the displacement of the anchor head is relatively stable,and the acceptance is qualified,greatly accelerating the tensioning time of the anchor cable,improving the construction speed of the project,and the cost is economically reasonable,provides a reference basis for future pile anchor support projects with narrow construction sites and tight construction periods.