摘要
以夯筑土遗址EBTP锚杆两锚系统为研究对象,分别开展间距为0.3 m和0.6 m的室内两锚DIC拉拔试验,明确荷载-位移关系与典型破坏模式;在此基础上,依据锚杆滑移失效特征,将承压段浆体/土体界面和受拉段杆体/浆体界面力学行为分别通过接触对和非线性弹簧模拟,提出锚固系统二维有限元数值模拟方法,结合试验结果验证了其可靠性.试验结果表明,间距0.3 m时锚杆间土体主要沿夯层水平开裂破坏,0.6m时以拉压转换位置为界呈30~45°的锥形开裂破坏,土体顶面最大开裂半径约24 cm,0.3 m间距相比0.6 m时承载力降低约7%;模拟分析显示,锚杆间距对群锚效应的影响较为显著,当间距大于0.6 m时群锚效应较为有限,与试验结果吻合较好;扩体深度与锚杆极限承载力近似线性相关;随着锚固长度的增加承载力增幅先大后小,群锚效应逐渐增强,但锚固长度增加引起的承载力的提升仍大于群锚效应造成的承载力损失.研究结果对夯筑土遗址EBTP锚杆群锚设计具有指导意义.
The study examined the two-anchor system of Extension-Type Bamboo/Rebar Tension-Pressure(EBTP)anchor rods in earthen sites.Indoor two-anchor digital image correlation(DIC)pullout tests with anchor spacing of o.3 m and 0.6 m were conducted to clarify the load-displacement relationship and typical failure modes.Based on the characteristics of anchor slip failure modes,a 2D finite element method(FEM)was proposed for the two-anchor system.The slurry/soil interface under compression and rod/pulp interface in tension were simulated using the contact pairs and nonlinear springs,respectively.Experimental results indicated that,at O.3 m spacing,horizontal cracking along the rammed earth layer was the primary failure mode,while at O.6 m spacing,a conical cracking pattern emerged with a transition between tension and compression at an angle of 30°~45°,yielding a maximum crack radius of approximate-ly 24 cm at the soil top surface.The bearing capacity decreased by approximately 7%at 0.3 m spacing compared to O.6 m spacing.The simulation analysis illustrates that anchor spacing has a significant influ-ence on the group anchor effect.For one thing,when the spacing exceeds O.6 m,the group anchor effect is more limited,which is consistent with experimental results.For another,the depth of the expansion body demonstrates an approximately linear correlation with the ultimate bearing capacity of the anchor.There-fore,as anchor length increases,the bearing capacity initially increases sharply,followed by a more mod-erate increase.Although the group anchor effect gradually strengthens,the increment in bearing capacity due to increased anchor length outweighs the loss caused by the group anchor effect.These findings pro-vide valuable insights for the design of EBTP anchor groups in earthen sites.The simulation methodology in this study can be used to predict and optimize anchorage design parameters for anchoring works at earth-en sites.
作者
芦苇
薛科
闫笑琦
刘加平
李东波
Wei Lu;Ke Xue;Xiaoqi Yan;Jiaping Liu;Dongbo Li(College of Science,Xi'an University of Architecture and Technology,Xi'an,710055;National Key Laboratory of Green Building,Xi'an University of Architecture and Technology,Xi'an,710055)
出处
《固体力学学报》
CAS
CSCD
北大核心
2024年第4期547-564,共18页
Chinese Journal of Solid Mechanics
基金
国家重点研发计划项目(2023YFF0906000)
国家自然科学基金项目(52008332,52378195)
中国博士后基金地区专项支持计划项目(2021M693877)
西部绿色建筑国家重点实验室自主研究课题基金项目(LSZZ202225)
西安建筑科技大学前沿交叉领域培育专项项目(X20220074)资助。
关键词
土遗址锚固
两锚同步拉拔试验
数值模拟
荷载-位移关系
群锚效应
anchorage of earthen sites
synchronous pullout test of two-anchor system
numerical simulation
load-displacement relationship
group anchor effect
