重塑碎石土地基螺旋锚抗拔模型试验及承载机理分析  

MODEL TESTS OF PULL-OUT RESISTANCE FOR HELICAL ANCHORS AND BEARING CHARACTERISTIC ANALYSIS IN REMOLDED GRAVEL FOUNDATION

作　　者：薛峰 丁士君 李海梅 秦之武 张海成 童海林 何增鑫 XUE Feng;DING Shijun;LI Haimei;QIN Zhiwu;ZHANG Haicheng;TONG Hailin;HE Zengxin(State Grid Qinghai Electric Power Corporation,Xining 810008,China;China Electric Power Research Institute,Beijing 100055,China;College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100124,China;State Grid Haibei Electric Power Supply Company,Haiyan 810029,China)

机构地区：[1]国网青海省电力公司,西宁810008 [2]中国电力科学研究院有限公司,北京100055 [3]北京工业大学建筑工程学院,北京100124 [4]国网海北供电公司,青海海晏810029

出　　处：《工业建筑》2021年第6期150-155,共6页Industrial Construction

摘　　要：为研究螺旋锚基础的适用性,促进其在碎石土地基中的应用,在室内开展了重塑碎石土地基螺旋锚整模和半模轴向上拔静载荷试验。基于上拔荷载-位移关系曲线、碎石土体纵断面裂缝分布及形态等试验结果,分析碎石土中螺旋锚抗拔承载特性,以及锚盘对其承载性能的影响,研究螺旋锚抗拔承载机理。结果表明:浅埋于碎石土中的锚盘往往发生整体剪切破坏并且承载力具有弱化现象,而深埋锚盘主要发生上部土体局部剪切破坏进而变形逐渐增大;螺旋锚承载过程初期,锚盘上部碎石土被挤密,荷载与位移呈近似线性关系,随着荷载的增大,锚盘上部土体被压缩、剪切,导致变形不断增大,最终导致承载失效;锚盘数量越多、埋深越大,螺旋锚抗拔承载力越大、变形越小,增加埋深对承载力影响在小位移时即可充分发挥作用。因此,碎石土中螺旋锚属于一种深基础,锚盘与土体的相互作用是影响其承载力的主要因素。In order to explore the applicability of helical anchor foundation and promote its application in gravel strata,the axial pull-out tests for complete-model and half-model helical anchors in remolded gravel ground were conducted in the laboratory.Based on the test results,the distribution and shape of longitudinal cracks in the gravel,the bearing characteristics of pull-out resistance for helical anchors in gravel and the effects of anchor plates on bearing capacity were analyzed.The bearing mechanisms of pull-out resistance for helical anchors were studied.The results showed that the general shear failure and bearing capacity weakening often occured to anchor plates shallowly emkedded in gravel strata,local shear failure usually occured in the upper soil stratum above anchor plates deeply embeded in gravel strata,which resulted in the deformation to increase continuously.Gravel strata above anchor plates at the initial stage of loading,and the relations between loads and displacement were approximately linear;with the increase of loading,soils above the anchor plates were compressed and sheared,which led to excessive deformation and bearing failure.The more the anchor plates,the deeper the embedment,the larger the bearing capacity of pull-out resistance and the smaller the deformation of the helical anchor.Increasing embedment could play a full role in bearing capacity of pull-out resistance at the stage of small displacement.Therefore,the helical anchors in gravel were a kind of deep foundations,and the interaction between anchor plates and soil was the main factor influcencing bearing capacity.

关 键 词：碎石土 螺旋锚 抗拔性能 模型试验 

分 类 号：TU473.1[建筑科学—结构工程]