【作者】 莫晨聪；

【导师】 汪波；

【作者基本信息】 西南交通大学 ， 建筑与土木工程（专业学位）， 2018， 硕士

【摘要】 近10年来,我国地下工程建设数量急速增长,进入了快速发展阶段。锚杆支护则因为施工便捷、工程造价较低、环境适应性强等优点,早已在地下工程领域得到广泛应用,成为其不可或缺的一部分。但目前在工程中对于垫板的详细选择并无理论依据。从而导致在恶劣环境下,垫板可能会发生严重变形。目前对于锚固系统受力情况的检测也十分困难。国内外对于锚固体系的研究,绝大多数集中于杆体自身,较少研究垫板的受力状况,尤其对于垫板与杆体间力学特定关系的研究更是鲜有涉及。在快速、准确、方便地测试出垫板及锚杆受力情况的同时,为后期依据两者间建立的相互力学关系,通过垫板受力特征来快速确定杆体力学特性,尤其是为预应力锚杆的施载效果提供重要的技术参考。研究成果具有非常重要科学意义与工程价值。本文以锚杆系统中的垫板与杆体为主要研究对象,采用室内试验的方法,基于光纤光栅传感技术的测试,揭示不同工况下垫板的适宜性及其与杆体间的力学特性关系,主要结论成果如下:(1)通过试验揭示了不同锚固形式(涨壳头固定与螺母固定)对锚杆轴力的影响性,结果显示二者并无显著差异,且随着施加荷载的变化,锚杆轴力与垫板应力基本为线性变化。验证了采用光纤光栅传感器测量锚杆轴力与垫板应力的可行性。(2)试验探明了锚杆的基本受力特性:即轴力沿杆体全长基本一致。试验结果表明:施加荷载越大,锚杆轴力越大。但试验测得锚杆轴力与施加的荷载并不相等,而是呈一定的倍数关系。当施加荷载大于10kN小于40kN时,施加荷载基本约为锚杆轴力的0.66倍。(3)通过试验揭示了锚杆系统采用碗形垫板和平板垫板起到的效果基本一致,反应出在硬岩条件下,垫板的形状对锚杆轴力无明显影响。(4)试验探明了在垂直与非垂直状态下垫板与杆体间的力学关系:在有球形垫圈情况时,垫板应力与锚杆轴力基本呈线性变化。当垫板倾斜角度小于20°时,倾斜角度变化对垫板与杆体的力学关系并无明显影响,即垫板倾斜角度变化对垫板应力、锚杆轴力亦影响较小。(5)试验揭示了在无球形垫圈的情况下,施加的荷载越大,锚杆受到的弯矩也就越大,易造成锚杆的永久形变。在无球形垫圈时,各个荷载情况下相应的最大锚杆轴力与垫板应力均大于有球形垫圈的情况,倾斜角度变化对垫板与杆体的力学特性影响较大。揭示了球形垫圈在锚固系统中的效用性。更多还原

【Abstract】 Over the past 10 years,the number of underground constructions in China has increased rapidly,entering a stage of rapid development.Bolt support has been widely used in the field of underground engineering because of its convenient construction,low cost and strong environmental adaptability,becoming an indispensable part of it.However,there is no theoretical basis for the selection of anchor plate in construction at present.This may lead to large deformation of the anchor plate in severe environment.It is also very difficult to detect the force of anchorage system.At home and abroad,most of the researches on anchorage system focus on the bolt body itself.The stress condition of the anchor plate is seldom studied.The relationship between the anchor plate and the bolt body is rarely involved.Knowing the stress condition of the anchor plate and the bolt body quickly,accurately,conveniently and establishing the relationship between them,which can help to quickly determine the mechanical properties of the bolt body according to the stress characteristics of the anchor plate,can provide technical references for the loading effect of prestressed anchor bolt.The research results are of great scientific significance and engineering value.In this paper,the anchor plate and the bolt body are the main research objects.Based on the fiber bragg grating sensing technology,laboratory tests were carried out,revealing the adaptability of the anchor plate and the mechanical relationship with the bolt body under different working conditions.The main results are as follows:(1)The influence of different anchorage forms(fixing by expansion shell and fixing by nut)on the axial force of rock bolt is revealed through tests.There is no significant difference between them.With the change of applied load,the axial force of the rock bolt and the stress of the anchor plate are linear change,proving the feasibility of using fiber bragg grating sensors to measure axial force of the rock bolt and the stress of the anchor plate.(2)The basic stress characteristics of the rock bolt are proved by the tests: The axial forces along the rock bolt are almost equal.The test results show that the greater the applied loads are,the greater the axial forces of the rock bolt will be.However,the axial forces of the rock bolt are not equal to the applied load,but showing a multiple relationship.When the applied load is greater than 10 kN and less than 40 kN,the applied load is approximately 0.66 times the axial force of the rock bolt.(3)Through the tests,it is revealed that the effect of the bowl shaped anchor plate and plate shaped anchor plate are almost the same in anchorage system,which shows that the shape of the anchor plate has no obvious effect on the axial force of the rock bolt under hard rock conditions.(4)The mechanical relationships between the anchor plate and the rock bolt body under vertical and non vertical conditions are revealed by tests: In the presence of the dome washer,the stress of the anchor plate and the axial force of the rock bolt are almost linear change.When the inclination angle is less than 20 degrees,the change of it has no obvious effect on the relationships between the anchor plate and rock bolt body,which means the change of the inclination angle has little effect on the stress of anchor plate and the axial force of the rock bolt.(5)When the inclination angle is less than 20 degrees,the change of it has no obvious effect on the axial force of the rock bolt body and the stress of the anchor plate.Different pull out methods have no effect on axial force of rock bolt body.(6)The tests reveal that without the dome washer,the greater the applied load is,the greater the bending moment of the rock bolt will be,which may lead to the permanent deformation of the rock bolt.Without the dome washer,the maximum axial forces of the rock bolt and the stresses of the anchor plate are greater than those of the rock bolt with dome washer under different working conditions and the change of the inclination angle has a great influence on the mechanical properties of the anchor plate and rock bolt body,revealing the utility of the dome washer in anchorage system.更多还原