花岗岩残积土层全黏结锚杆荷载传递特性试验研究  

Experimental study on load transfer characteristics of fully bonded anchors in granite residual soil layer

作　　者：付文光 强小俊 郎向伟 肖莉萍 FU Wenguang;QIANG Xiaojun;LANG Xiangwei;XIAO Liping(School of Civil Engineering,Tianjin University,Tianjin 300350,China;Shenzhen Geological Environment Research Institute Co.,Ltd.,Shenzhen 518063,China;Guangdong Engineering and Technology Research Center for Geotechnique and Underground Space,Shenzhen,518063,China;Railway Science(Shenzhen)Research and Design Institute Co.LTD,518063,China;Shenzhen GongKan Geotechnical Group Co.,LTD,Shenzhen 518063,China)

机构地区：[1]天津大学建筑工程学院,天津300350 [2]深圳市地质环境研究院有限公司,广东深圳518063 [3]广东省岩土与地下空间工程技术研究中心,广东深圳518063 [4]铁科院(深圳)研究设计院有限公司,广东深圳518052 [5]深圳市工勘岩土集团有限公司,广东深圳518063

出　　处：《岩土工程学报》2024年第12期2548-2558,共11页Chinese Journal of Geotechnical Engineering

基　　金：福建省科技计划项目(2022I0014)。

摘　　要：业界对锚杆锚固体与地层界面的荷载传递特性有着丰富研究成果,但对黏性土层中界面黏结应力集中、应力峰值转移、临界锚固长度及锚固效率等问题仍感到困惑。为此,深坪锚杆试验在花岗岩残积黏性土层中按常规施工水平制作了23根足尺全黏结锚杆,部分锚杆埋设了分布式光纤,采用新型张拉设备进行荷载试验,结果表明:①在锚固体18m长度范围内,全黏结锚杆极限抗拔承载力随长度近似线性增加,超过18m后锚固效率逐渐降低;②锚固体前半段黏结应力尚未达到黏结强度就会向后半段传递,锚固体较短时先传递到锚杆底端再几乎全长增大至黏结强度,较长时前半段先达到黏结强度再向后传递到底端、后半段再接近或几乎达到黏结强度;③浆体拉应力沿轴向分布曲线可分为快速增加、减速增加、慢速减少、归零共4段;④锚固体复合刚度主要体现为锚筋刚度,计算锚固体复合模量时浆体不应采用弹性模量。There are abundant research results on the load transfer characteristics of the grout/ground interface of the ground anchors in the industry,but the problems in the cohesive soil layer are still confused such as interface bond stress concentration,stress peak transfer,critical fixed length and anchoring efficiency,etc.For these purpose,according to the normal construction level,23 full-length fully bonded anchors are constructed in the granite residual clay within the Shenping Anchor tests,and some anchors are embedded with distributed optical fiber.The results of load tests with new type jack and distributed optical fiber tests show that:(1)The ultimate pullout resistance of fully bonded anchor increases approximately linearly with the length in the whole 18 m fixed length,and the anchoring efficiency gradually decreases over 18 m.(2)The bond stress of the front part of anchor will be transferred to the latter part before the bond strength is reached.The stress will be transferred to the anchor end for a short length and then increase to the bond strength in the nearly whole length,while for a long length,the stress of the front part reaches the bond strength first,then passes back to the end,the latter part approaches or almost reaches the bond strength lastly.(3)The axial distribution curve of grout tensile stress can be divided into four sections such as rapid increase,deceleration increase,slow decrease and return to zero.(4)The composite stiffness of anchor body is mainly reflected on the stiffness of tendon,and the composite modulus of fixed length should not be calculated according to the elastic modulus of grout body.

关 键 词：深坪锚杆试验 分布式光纤 浆地界面 临界锚固长度 应力集中 

分 类 号：TU470[建筑科学—结构工程]