岩土锚杆拉拔荷载传递分析与FRP智能锚杆监测验证

发布时间：2018-10-08 15:10

【摘要】：我国是世界上地质灾害最为严重的国家之一。锚杆支护技术具有充分调动岩土体强度、减轻结构物自重以及节约工程材料等优点，近年来已逐渐发展为地质灾害预防与治理的主要技术手段，在边坡、基坑以及隧道等岩土工程领域得到了广泛应用。但是，由于加固对象和工作环境的复杂性，至今锚杆支护原理仍没有形成一个统一和全面的认识，对于复杂条件下锚杆的应力分布与传递规律以及检测与监测技术等问题亟需更为深入的研究。本文采用理论分析、试验实测以及工程应用相结合的方法，围绕锚杆拉拔荷载传递与内嵌光纤传感的全尺度监测验证展开了较系统研究，主要内容包括：首先，考虑界面非线性特性，从锚杆荷载位移的指数曲线关系出发，建立了锚固界面的曲线剪切滑移模型；采用荷载传递函数法推导了张拉荷载作用下锚杆的荷载传递解析解，并通过室内和现场实测锚杆拉拔试验数据进行了验证，对锚杆拉拔受力特征进行了分析。其次，考虑界面残余剪切强度影响，进一步拓展了锚固界面的曲线剪切滑移模型，利用切比雪夫多项式推导了该模型下锚杆的荷载传递解析解，分析了不同残余剪切强度条件下锚杆的拉拔受力特征，并通过实测数据对模型和荷载传递解答进行了验证。第三，考虑岩土局部脱空不连续特征，结合上述建立的曲线剪切滑移模型及分析方法，构建了局部脱空岩土锚杆锚固段的拉拔荷载传递解答，对局部脱空岩土锚杆锚固段的拉拔荷载传递特征进行了探讨，分析了局部脱空参数对锚杆锚固段拉拔荷载传递特征的影响。最后，针对实际工程锚杆拉拔受力长期测试的全尺度监测需求，在阐述光纤传感技术原理的基础上，研制了系列内嵌光纤FRP智能锚杆，并对其制备工艺进行了探讨；基于研制的智能锚杆，对均质和局部脱空岩土锚杆的受力特征进行了拉拔试验研究，分析了上述工况智能锚杆的应力分布和界面损伤特征，探讨了智能锚杆对应力分布和界面损伤的全尺度监测性能，并对比分析了智能锚杆的全尺度监测与理论计算结果，验证了智能锚杆的全尺度监测性能和解析解的有效性。在此基础上，结合某边坡工程的实际监测需求，采用内嵌光纤FRP智能锚杆对边坡加固锚杆的应力状态进行了监测，获得了边坡锚杆的应力分布特征和演化规律，，验证了智能锚杆在实际工程中应用的有效性和可靠性。
[Abstract]:China is one of the most serious geological disasters in the world. Bolt support technology has the advantages of fully mobilizing the strength of rock and soil mass, reducing the weight of structure and saving engineering materials. In recent years, it has gradually developed into the main technical means of geological disaster prevention and control in slope. The field of geotechnical engineering, such as foundation pit and tunnel, has been widely used. However, due to the complexity of reinforcement objects and working environment, the principle of bolting has not yet formed a unified and comprehensive understanding. It is necessary to study the stress distribution and transfer law, detection and monitoring technology of anchor rod under complex conditions. In this paper, theoretical analysis, experimental measurement and engineering application are used to study systematically the full-scale monitoring and verification of anchor pull load transfer and embedded fiber optic sensing. The main contents are as follows: first, Considering the nonlinear characteristics of the interface, starting from the exponential curve relation of the load displacement of the anchor rod, the curve shear slip model of the anchor interface is established, and the analytical solution of the load transfer of the anchor rod under tension load is derived by using the load transfer function method. The results are verified by indoor and field test data, and the mechanical characteristics of bolt drawing are analyzed. Secondly, considering the influence of interfacial residual shear strength, the curve shear slip model of Anchorage interface is further extended, and the analytical solution of load transfer of anchor rod under the model is derived by Chebyshev polynomial. In this paper, the tensile force characteristics of anchor rod under different residual shear strength are analyzed, and the model and load transfer solution are verified by measured data. Thirdly, considering the discontinuous characteristics of local detachment of rock and soil, combined with the curve shear slip model established above and the analytical method, the drawing load transfer solution of the anchoring section of local detachment rock and soil is constructed. In this paper, the characteristics of pull-out load transfer in anchoring section of rock and soil anchors are discussed, and the influence of local detachment parameters on the load transfer characteristics of anchoring section is analyzed. Finally, according to the requirement of full-scale monitoring for long-term testing of pulling force of practical engineering anchor, a series of embedded optical fiber FRP intelligent anchors are developed on the basis of explaining the principle of optical fiber sensing technology, and the preparation process is discussed. Based on the developed intelligent anchor rod, the stress distribution and interface damage characteristics of the intelligent anchor rod under the above conditions are analyzed by drawing test and research on the mechanical characteristics of the homogeneous and partially detached rock and soil anchors. The full-scale monitoring performance of intelligent anchor to stress distribution and interface damage is discussed. The results of full-scale monitoring and theoretical calculation of intelligent anchor are compared and analyzed. The effectiveness of the analytical solution and the full-scale monitoring performance of intelligent anchor are verified. On this basis, combined with the actual monitoring requirements of a slope engineering, the stress state of the slope reinforced anchor is monitored by embedded optical fiber FRP intelligent anchor, and the stress distribution characteristics and evolution law of the slope anchor are obtained. The validity and reliability of the application of intelligent bolt in practical engineering are verified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476

【参考文献】