【作者】 陈弦；

【导师】 谷拴成；

【作者基本信息】 西安科技大学 ， 岩土工程， 2010， 硕士

【摘要】 锚杆支护是提高岩土工程稳定性和解决复杂岩土工程问题最有效的手段之一,在边坡工程,隧道工程、采矿工程和基坑工程等领域得到了广泛的应用。现场拉拔试验是检测锚杆锚固质量的重要手段之一,锚杆应力的分布不均匀导致对锚杆抗拔力的测量并不能完全的反应锚杆的锚固状态。因此,拉拔荷载传递机理的正确描述对锚杆的设计具有重要工程意义。本文通过弹塑性理论分析和现场拉拔试验对锚杆的荷载传递、锚杆的破坏过程以及锚固层界面的参数进行了深入的研究。取得了一些有意义的成果:1、对锚杆的破坏模式和锚固机理进行了分析。阐述了锚杆在拉拔荷载作用下失效的方式和原因。分析了在锚固段的荷载传递过程中,两个界面之间粘结力的作用机理和力学行为。2、总结了已有的锚固体与岩体之间的剪切滑移本构关系模型。基于B.Benmokrane等建立的孔壁界面的剪切滑移本构模型,采用荷载传递函数法,建立弹塑性理论空间模型,得到了锚杆界面上剪应力沿锚杆分布的理论解。研究表明,锚固体与岩石界面可以分为残余剪切阶段,塑性软化阶段和弹性变形阶段,不同位置处的界面满足不同剪应力分布规律。并对影响锚杆锚固效果的因素进行了系统的分析。3、通过现场黄土层锚杆拉拔试验,得到了沿锚固体的应力分布规律,并与理论结果进行对比分析,吻合较好。针对柠条塔煤矿矿井支护的锚杆进行现场拉拔试验研究,得出了煤岩体中的锚杆在树脂锚固剂作用下的荷载位移全过程曲线。通过锚杆拉拔特征曲线对锚固层界面的破坏过程进行分析,得到了界面破坏过程分为:弹性变形阶段、滑移变形阶段、脱粘出现与发展阶段和完全脱粘阶段。4、推导了锚固层界面极限抗剪强度参数与锚杆拉拔P-S曲线之间的关系,结合煤巷现场试验得到的P-S曲线数据,计算得到树脂锚固剂与煤岩体之间的抗剪强度参数;针对黄土层现场试验得到的应力分布规律,通过分析计算,得到了黄土与砂浆界面的抗剪强度参数。为锚固体抗剪强度参数的确定提供了一套切实可行的办法,对锚杆的设计具有一定的指导意义。更多还原

【Abstract】 Anchor is one of the effective methods to improve the stability of geotechnical engineering and solve the complex geotechnical engineering problems. It is widely used in slope, tunnel, mining, foundation ditch and so on. On-site pull-out tests is one of the important methods to detect the quality of anchor. Proper evaluation on the status of bolting system is greatly significant for anchor design in projects domain. Based on elastic-plastic theoretical analysis and pull-out tests ,the load transfer and failure process of anchor bolt and the parameters of anchoring layer interface was discussed in the paper. Get some significant results:The failure mode and anchorage mechanism of bolt anchor and mechanism has been analyzed. The failure mode and reason under the drawing load were elaborated. In the process of load transfer, the bond mechanism and mechanical behavior of two interfaces were analyzed.The existing shear slip model between the anchorage and the rock mass has been summarized. Based on the shear slip model of pore wall which built by B.Benmokrane, taking the load transfer function method, a elastic-plastic model was set up for the theoretical solution of the shearing stress distribution law along the length direction. Research shows that anchor solid rock interface can be divided into the residual shear stage, plastic softening stage and elastic deformation stage, and the different position of interface has different shear stress distribution. And the factors which influence the anchoring effect were analyzed exactly.By the field experiment of bolt in loess, the stress distribution along the anchorage was measured. The test results are in good agreement with the theory analysis results. For the bolt of supporting in Ningtiaota Coal Mine, the pull-out test has been taken in the roadway. By the test, we get the whole load-displacement curve of the bolt with the resin in the coal. Based on the characteristic pull out curve, the failure process of interface is analyzed and the process is divided into: elastic deformation stage, sliding deformation stage and debonding appearance and development stage and completely debonding stage.The formula between the limit shear strength parameter and the bolt P-S curve was derived. By the data of field anchor tests, the shear strength parameters between the resin and coal were calculated. Based on the stress distribution of bolt in loess, the shear strength parameter between the loess and mortar was calculated. They provide a feasible way to get the shear strength parameters and give a reference for following design.更多还原