高聚物锚固体与土体黏结特征试验与数值模拟

Experimental and numerical simulation on bond behavior between polymer anchorage body and soil

针对高聚物锚固体与土体相互作用机理认识不足、黏结强度参数不完善的问题,采用中心拉拔的大比尺模型试验,测试了低密度(0.11~0.13 g/cm^3)高聚物锚固体与土体间的黏结特性,获得了锚杆加载端的荷载-位移曲线以及锚杆轴力、界面黏结力的分布规律,得出了低密度高聚物锚固体与不同状态土体的黏结强度值;从细观力学角度出发,采用颗粒流软件(PFC2d),建立了锚杆杆体-高聚物锚固体-土体的三相锚固体系数值模型,对拉拔荷载作用下高聚物锚固机理进行分析,通过和模型试验结果的对比,验证了数值模型的合理性,并重点探讨了土体应力和孔隙率的变化规律。试验结果为高聚物锚固注浆设计及应用提供了参数依据,颗粒流模型为高聚物锚固机理的细观尺度研究提供了一种可行的手段。

In view of insufficient recognition of the mechanism of interaction between polymer anchoragebody and soil as well as imperfect bond strength parameters,the bonding behavior between the low density（0.11～0.13 g/cm3） polymer anchorage body and different status soil was studied by the large-scale modelof concentric pull-out tests,and the load-displacement curve of loading end,the distribution of axial forceand cohesive stress were obtained as well as the empirical value of the cohesive strength was put forward.From the view of micromechanics,the numerical model of anchor bolt-polymer anchorage body-soil systemswas established by Particle Flow Code in 2 dimensions（PFC2D） software, and the anchoring mechanismof polymer anchorage body under pull-out load was analyzed. In addition, the rationality of the numericalmodel was verified by comparing with the model test results,and the variation law of stress and the porosi-ty of soil were discussed emphatically. The experimental results provide the parametric basis for the designand application of polymer anchorage grouting,and the particle flow model provides a feasible tool for mi-cro-scale study of the polymer anchorage mechanism.