扩体锚杆拉拔破坏机制模型试验研究  

MODEL TEST RESEARCH ON FAILURE MECHANISM OF UNDERREAMED GROUND ANCHOR

作　　者：郭钢[1,2] 刘钟[1,2] 李永康[3] 杨松[1,2] 张义[1,2] 

机构地区：[1]中冶建筑研究总院有限公司,北京100088 [2]中国京冶工程技术有限公司,北京100088 [3]中国冶金科工集团有限公司,北京100020

出　　处：《岩石力学与工程学报》2013年第8期1677-1684,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：新型扩体锚固技术及机具装备研发(财企[2012]171)

摘　　要：扩体锚杆拉拔过程中的锚周破坏体形态对于研究扩体锚杆的承载机制具有重要意义。为能够清晰地对锚周土体在锚杆拉拔过程中的破坏体形态进行观测与分析,应用数字照相变形量测技术对竖直拉拔的扩体锚杆进行一系列室内模型试验,得到扩体锚杆锚周砂土全变形场数字图像分析结果。试验结果与分析表明,深埋扩体锚杆破坏体形成于土层表面以下,呈封闭气球形。在极限承载力状态出现前,破坏体范围不断扩大,而在此之后,破坏体范围不再扩大,其内部土体被大幅压缩挤密。锚周土体剪切带在全过程中呈竖直的狭长带状,破坏体范围内的剪应变幅度不断增大。在此过程中,扩体段顶面以上的砂土发生体积压缩而侧面部分土体膨胀。在此基础上,建议以实际观测的破坏体形式建立扩体锚杆破坏模型与承载力计算方法。The rupture surface of underreamed ground anchor is essentially important for the bearing mechanism of underreamed ground anchor. In order to observe the shape of rupture surface of sand around underreamed ground anchor during uplifting, a series of model tests on underreamed ground anchor under vertical uplifting were carried out with digital photogrammetry. For the first time, the whole deformation fields of underreamed ground anchor were captured through digital deformation analysis. The results show that the shear bands in the whole process exhibited as long and narrow vertical strips. The shear strain amplitude inside the rupture surface increased. During the process, the sand above the top surface of underreamed section exhibited volumetric compression; while the volume of sand on the side of underreamed section expanded. Based on the analysis, the damage model and bearing capacity calculation method of underreamed ground anchor should be established according to the rupture surface through actual observations.

关 键 词：岩土工程 扩体锚杆 剪切应变 承载力 

分 类 号：TU4[建筑科学—土工工程]