拉力型锚杆合理锚固长度分析  

Analysis on reasonable anchor length of tensile anchor

作　　者：马天忠[1,2,3] 安子申 周勇[1] 王正振 苏天涛[1,2,3] 高虹 MA Tian-zhong;AN Zi-shen;ZHOU Yong;WANG Zheng-zhen;SU Tian-tao;GAO Hong(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;Key Laboratory of Disaster Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;Western Center of Disaster Mitigation in Civil Engineering,Ministryof Education,LanzhouUniversity of Technology,Lanzhou 730050,Gansu,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [3]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050

出　　处：《长安大学学报（自然科学版）》2022年第5期43-51,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(52068048);甘肃省自然科学基金项目(21JR11RM052,1308RJZA140);甘肃省住房和城乡建设厅建设科技项目(JK2022-03)。

摘　　要：针对锚固系统的主要结构往往埋置于岩体内部,现有关于锚固段长度的计算公式过于繁琐,且岩土工程从业人员多采用经验法进行设计和施工的问题,采用理论推导与实际工程相结合的方法,从锚杆微元体的受力分析入手,给出锚固段微元体受力平衡方程,得到锚杆极限抗拔承载力的计算公式,并以此为基础推导出改进后的锚杆合理锚固长度计算公式。结合现行规范,给出拉力型锚杆合理锚固长度的有效变化范围;通过改变锚杆入射角的大小,结合锚杆内力几何关系分布图,推导得出锚杆倾角变化后的锚固段长度计算修正方法。探究锚杆杆体直径的变化规律,给出其合理的变化范围,并基于兰州市某实际边坡工程,验证该公式计算的锚固段合理锚固长度取值范围的合理性。研究结果表明:在同一支护结构中,入射角大的锚杆通常其锚固长度也有所增大,验证了提出的锚杆倾角变化后锚固段长度计算修正方法的合理性;得出影响锚杆抗拔能力的因素主要有界面抗剪强度参数、锚固段长度、钻孔直径等,但必须在一定范围内提高其数值,才可以有效提升支护体系的支护能力。Aiming at the main structure of the anchoring system was often embedded in the rock mass, and the existing calculation formula for the length of the anchoring section is too complicated, and the geotechnical engineering practitioners mostly use the empirical method for design and construction. The method of combining theoretical derivation and practical engineering was adopted and started with the force analysis of the anchor rod micro-element. The force balance equation of the micro-element of the anchoring section was given and the formula of the ultimate pull-out bearing capacity of the anchor was obtained. Based on this, the improved formula for calculating the reasonable anchorage length of the bolt was derived. Combined with the current specification, the effective variation range of the reasonable anchoring length of the tension anchor was given. By changing the size of the incident angle of the bolt, the geometric relationship distribution diagram of the internal force of the bolt was combined. After deducing the change of the inclination angle of the anchor rod, the correction method of the length calculation of the anchoring section was obtained. After exploring the variation law of the diameter of the bolt body, the reasonable variation range was given. And based on an actual slope project in Lanzhou City, the rationality of the reasonable anchorage length range of the anchorage section calculated by this formula was verified. The results show that in the same supporting structure, the anchoring length of the anchor rod with a large incident angle is usually increased, which verifies the rationality of the proposed anchoring length correction method after the anchor rod inclination angle changes. It is concluded that the main factors affecting the pullout resistance of the bolt are the interface shear strength parameters, the length of the anchoring section, the diameter of the borehole, etc., but the values must be increased within a certain range to effectively improve the supporting capacity of the

关 键 词：道路工程 边坡工程 锚固系统 锚固长度 锚杆倾角 杆体直径 

分 类 号：U417.116[交通运输工程—道路与铁道工程]