压力型锚索力学机理现场试验研究

Field pull-out test and behavior analysis of compression type rock anchor cables

通过现场试验研究了岩质边坡中压力型锚索的受力和破坏机理。试验锚索采用130 mm孔径,6束标准钢绞线,符合实际工程的常用锚索规格。严格控制锚固段与非锚固段尺寸,设置了不同的锚固段长度用以研究锚索的抗拔力学性能。试验获得了岩质条件下足尺压力型锚索的荷载位移全曲线。用应变砖测试了锚固段注浆体在受力过程中的应变规律,测试结果与理论计算的结果吻合。对试验结果进行分析发现,在较软岩条件下,试验锚索的最佳锚固长度在2 m左右。压力型锚索的位移延性性能非常优秀,在锚索整体位移较大时还能维持较高的承载力,可以提供良好的破坏预警。根据实测的轴向应变发现,随着锚固长度的增加,应力传递长度也略有增加。提出压力型锚索的破坏要经历局部塑性,整体塑性两个阶段。

Behavior of compression type rock anchor cable in soft rock slope is studied by field test.Experimental anchor cables which have 130mm diameter holes and 6 steel strands are frequently used in anchorage of rock mass engineering.Various fixed anchor length and free anchor length are designed to find the whole loading-displacement relationship of test rock anchor cables.Strain sensors are put into cement paste to test the strain distribution curve of fixed anchor length.Test data coincide with theoretical results.The optimum fixed anchor length of experimental anchor cables is 2m.Ductility and residual strength of anchor cables are also excellent.Anchor cables still keep high bearing capacity when they have large displacement,which can also provide early failure warning.According to experimental strain data,stress transmission length become longer when bonded transmission length doing so.The failure of anchor cables has two stages of the partial plasticity and the whole plasticity.