预应力锚索锚固段界面滑移的细观力学分析

 在预应力锚索锚固段界面力学特性试验的基础上，研究锚固体界面在荷载作用下的变形规律及失效条件。试验结果表明，锚固力的大小与锚固长度有关，但不是成比例关系；当锚固长度达一定值时，再进一步增加锚固长度，锚固力的增大是非常有限的；在保证砂浆具有一定强度的条件下，含砂量越高的锚固体，其锚固力越大。从细观层面上对预应力锚索锚固段从弹性变形到塑性滑移以至脱黏失效的过程进行研究，结果表明，锚固体界面层是具有一定厚度并具有特殊力学性质的材料，其力学性质不仅与岩土体的性质有关，而且与灌浆体的材料组构密切相关；降低灌浆材料的水灰比，加入减水剂和其他外加剂对提高界面层的强度性能有着重要的意义；可将锚固体界面上的变形分为弹性变形、塑性滑移变形和脱黏变形3个阶段。由于锚固体界面层的剪胀效应，在滑移段中，越靠近荷载的近端，锚固体所受的剪应力越大；在整个锚固体中，主要的受力部分是塑性滑移区，而弹性区和脱黏区的受力都较小。

ANALYSIS OF INTERFACIAL SLIP MESOMECHANICS IN ANCHORAGE SECTION OF PRESTRESSED ANCHOR CABLE

Based on the test of interfacial mechanics of prestressed anchorage segment，the interfacial deformation laws and the failure conditions under different loads are studied. The test results show that anchoring strength is related to anchorage length but not with proportion relationship. When anchorage length reaches a constant value，the increase of anchoring strength is limited although with further increase of anchorage length. Under the condition，the strength of sand pulp is fixed，and the higher the sand-bearing capacity in the anchorage body is，the larger the anchoring strength is. The process from elastic deformation to plastic slip and up to debonding failure is studied on the mesoscopic level. It is demonstrated that anchorage body interfacial layer is a material with a certain thickness and special mechanical properties，whose mechanical properties are related to property of rock-soil body and closely to the material fabric of grouting body. So the mechanical properties of interfacial body will be effectively promoted based on the research on composition and mixture ratio of grouting materials，by which the anchoring strength will be improved. Deformation of one point on interface of anchorage body can be divided into three stages，i.e. elastic deformation，plastic-slipping deformation and debonding deformation. Because of the debonding effect of interface layer of anchorage body，the nearer it is to proximal end of load，the larger shear stress the anchorage body will bear. Within the whole anchorage system，the main stressed area is plastic-slipping zone；and the stresses born by elastic zone and debonding zone are relatively smaller.