拉压分散型锚索锚固机制及工程应用研究

近年来，结合拉力型、压力型以及荷载分散型锚索特点于一体的拉压分散型锚索在工程中有一定的应用，但内锚固段锚固机制以及设计方法研究尚不成熟。基于Kelvin解，分别推导拉力分散型锚索和压力分散型锚索的内锚固段与周围岩土体之间的剪应力解析解，再根据叠加原理得到了拉压分散型锚索内锚固段剪应力简化计算方法；基于理论成果将拉压分散型锚索应用于工程实例中，分别进行了拉压分散型锚索的基本性能试验及与拉力分散型锚索的预应力损失对比测试。通过算例分析结果表明，单元锚固体的两端剪应力较大，中间较小，剪应力的分布特征与现有文献资料模型试验及数值模拟结果相吻合；根据锚索的基本性能试验结果，按照本文计算方法得到了压力段和拉力段剪应力峰值强度，与已有的研究成果根据岩石单轴抗压强度得到的压力型和拉力型锚杆锚固段剪应力峰值强度结果基本吻合；经对锚索预应力损失测试结果分析及工程的长期监测，拉压分散型锚索在工程应用中荷载传递稳定可靠，工程应用效果良好。

Study on anchorage mechanism and application of tension-compression dispersive anchor cable

A new tension-compression dispersive anchor cable was recently adopted in projects, which is based on the combination of tension, compression and load dispersive anchor cables. However, there is a limited study on the mechanism and design method of the anchor cable. Based on the Kelvin solution, we derived analytical solutions of the shear stress between surrounding rock (soil) and the anchoring segments of the tension-dispersive and compression-dispersive anchor cables, respectively. According to the superposition principle, a simplified calculation method was proposed to obtain the shear stress between anchoring segment and surrounding rock (soil). On the basis of theoretical results, the new anchor cable was applied in practical engineering, and the basic performance test of the anchor cable and the comparison with the prestress loss of the tension-dispersed anchor cable were performed, respectively. Theoretical results indicated that the values of shear stress at both ends of the unit anchoring segment were relatively higher, while the stress reached the lowest in the middle. The distribution characteristics of shear stress were consistent with testing results in the literature and numerical simulation results. According to testing results, i.e., the bearing capacity of the anchor cable, the peak values of shear stress in tension and compression sections were obtained using the simplified method, which agreed well with peak values of shear stress by means of the uniaxial compressive strength of rock in tension and compression anchor cables. The comparison results and the long-term monitoring data reveal that the effect of engineering application is good, and the load transfer of the anchor cable is stable and reliable.