膨胀土锚杆(索)承载变形性状试验研究  

Experimental study on bearing deformation behavior of anchor (cable) inexpansive soil

作　　者：洪顺生 吴江斌[2] 冯宇飞 HONG Shun-sheng;WU Jiang-bin;FENG Yu-fei(Zhejiang Geology and Mineral Construction Co.,Ltd.,Hangzhou 310063,Zhejiang,China;East China Architectural Design and Research Institute Co.,Ltd.,Shanghai 200001,China)

机构地区：[1]浙江省地矿建设有限公司,浙江杭州310063 [2]华东建筑设计研究院有限公司,上海200001

出　　处：《地基处理》2023年第6期483-491,共9页Journal of Ground Improvement

基　　金：云南省科技厅科技计划项目(202303AA080012)。

摘　　要：针对蒙自盆地膨胀土地区高边坡设计需求,开展了锚杆(索)基本试验,包括全长黏结型锚杆、拉力型锚索、拉力分散型锚索,涉及黏土、全风化泥灰岩、强风化泥灰岩等地层。试验结果表明:现场实测极限黏结强度约为规范推荐值qsk的1.2~1.9倍;在相同的锚固土层中,锚固长度15 m的锚杆黏结强度比锚固长度10 m的锚杆小约16%;全长黏结型锚杆与拉力型锚索在循环荷载-位移曲线形态上有较大差别,前者曲线滞回环呈细长型,后者出现了较大的滞回环;累积荷载-位移曲线表现出明显的非线性,塑性位移约占总位移的30%~66%,多循环曲线割线斜率约为单循环的50%;规范推荐锚杆(索)刚度估算公式没有考虑锚固体与土体之间的变形,与实测相比,会大幅高估全长黏结型锚杆的刚度。试验成果可为认识膨胀土地区锚杆(索)的承载性状和指导高边坡支护设计提供基础性数据。In compliance with the design specifications for high slopes in the expansive soil region of the Mengzi basin,we conducted fundamental tests on various anchor systems,including full-length bonded anchors,tensile anchor cables,and tensile dispersed anchor cables,across different soil types such as red clay,completely weathered mudstone,and strongly weathered mudstone.Test results reveal that the measured ultimate bond strength ranges from 1.2 to 1.9 times the recommended value qsk specified in the code.For anchors located within the same soil layer,the ultimate bond strength of 15 m anchors is approximately 16%less than that of the 10 m anchors.Notably,the cyclic load displacement curves exhibit significant variations between full-length bonded anchors and tensile anchor cables.The former display slender hysteretic loops,while the latter exhibit larger hysteretic loops.The cumulative load displacement curves clearly manifest nonlinearity.Plastic displacement constitutes approximately 30%to 66%of the total displacement,and the secant slopes in multi-cycle curves amount to about 50%of those in single-cycle curves.Importantly,the anchor(cable)stiffness estimation formula recommended in the code does not account for deformation between the anchor body and the soil.This results in a significant overestimation of the stiffness of full-length bonded anchors when compared to actual measurements.These test results offer fundamental data for comprehending the load-bearing characteristics of anchors(cables)in expansive soil areas and for guiding the design of support systems for high slopes.

关 键 词：膨胀土 锚杆(索) 承载力试验 黏结强度 变形 刚度 

分 类 号：TU443[建筑科学—岩土工程]