微型桩的被动锚固作用机理

Passive anchoring mechanism of micropile system

在总结前人对微型桩研究成果的基础上,通过室内试验研究了微型桩支护体系的水平支挡作用,提出为了提高滑体的锚固力、降低滑体变形,可以在桩顶设置与桩刚性连接或铰接的混凝土顶梁;通过模型分析,详细论述了微型桩加固滑坡的被动锚固机理,推导了钢材强度控制下的锚固力计算公式;与锚杆(索)的锚固相比较,提出了微型桩治理滑坡时,滑面以下的锚固段在岩层中要确保6 m以上,而在土层中要确保8 m以上,此时微型桩的锚固力由钢材强度控制的锚固力C和地层所能提供的锚固力Tu中的最小值确定;通过工程实例分析,证明了微型桩治理滑坡的可行性与计算方法的可靠性。

Based on the achievement of the predecessors＇ research on micropiles, supporting system of the micropile horizontal resistance function is studied through the laboratory test. It is pointed out that the horizontal re- sistance force can be ignored and the rigid joint or hinged joint concrete beam are fixed on pile top in order to im- prove the slippery body of anchorage force and reduce sliding body deformation. Through the analysis of the model, the passive anchorage mechanism about landslide reinforcement of micropiles was discussed, and the calculation formula of the anchoring force under the control of the strength of steel was deduced. And the micropile anchor is compared to the anchor rod （cable）, it is put forward that the length of anchoring section should be more than 6 m in rock formation and 8 m in the soil layer. The anchorage force depends on the smaller one between ＂C＂ which is determined by material strength and ＂Tu＂ which depends on the stratus condition. In the end, the feasibility of mi- cropile control of the landslide and the reliability of the calculation method through an engineering example have been proved.