摘要
预应力锚索复合土钉支护是复合土钉支护中常用而有效的一种方法,目前对该支护方法的作用机制进行系统分析的不多,对其进行现场测试研究的也较少。首先对预应力锚索复合土钉支护的作用机制进行分析,然后通过现场测试和有限元模拟,对预应力锚索复合土钉支护作用时土钉锚索的内力和基坑的位移进行研究,揭示了预应力锚索复合土钉支护的内力和变形特征。测试和模拟结果表明:(1)实测值和有限元模拟结果较为吻合;(2)在预应力锚索复合土钉支护作用下,被支护土体弹性模量和黏聚力等力学参数将得到较大提高;(3)土钉的内力和变形具有开挖效应;(4)采用预应力锚索可以分担更大的土压力,并可减缓土钉内力的增长速度;(5)使用该方法时作用于面层的土压力并不显著;(6)基坑水平位移呈上下小、中间大的鼓状分布,垂直位移的分布规律和使用传统方法的结论基本一致,但水平位移和垂直位移均得到较好的控制;(7)预应力锚索复合土钉支护技术可以逐步增加支护结构的支护能力,较好地满足了基坑受不确定因素和施工过程因素的影响。研究结果可以为预应力锚索复合土钉支护方法的设计和施工提供科学的依据。
As an efficient supporting method,prestressed anchor cable composite soil nailing is widely adopted in geotechnical engineering.But the analysis of prestressed anchor mechanism is not sufficient.And the research on in-situ test of prestressed anchor cable composite soil nailing is seldom seen.Firstly,a brief introduction to the mechanism of prestressed anchor cable composite soil is given.Then,the horizontal and vertical displacements of foundation pit supported by prestressed anchor cable composite soil nailing are presented.The stresses of soil nailing and anchor head of prestressed anchor cable under excavation are also attained.Finally,the characteristics of stress and deformation of the prestressed anchor cable composite soil nailing with ANSYS10.0 are analyzed.Conclusions can be drawn as follows：（1） the results from in-situ test are in accordance with those from FEM simulation;（2） cohesion and elastic models of the soil in foundation pit,which is supported by prestressed anchor cable composite soil nailing,will be improved;（3） more earth pressure is shared by the anchor cable,and earth pressure shared by soil nailing is reduced for prestressed anchor cable composite soil nailing supporting;（4） earth pressure on the side of foundation pit is smaller when prestressed anchor cable composite soil nailing supporting is introduced;（5） the stress and deformation of soil nailing and prestressed anchor cable both have the excavation effect,time effect and space effect;（6） the horizontal deformation of the side of foundation pit is drum-shaped,and the vertical deformation of the side of foundation pit agrees well conventional rule;（7） the deformations of foundation pit,including the horizontal displacement and the vertical displacement,are better controlled when using prestressed anchor cable composite soil nailing supporting;and（8） prestressed anchor cable composite soil nailing supporting technique can gradually improve the supporting capacity during excavation,which satisfies the requirements of variations of the stress and deformation induced by the construction process and some uncertain factors.The achieved results can provide some references to the design and construction of similar projects.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2008年第2期410-417,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50279056)
广东省自然科学基金资助项目(031601)
广东省科技计划重点基金项目(2004B32801002)
关键词
土力学
预应力锚索
复合土钉
现场测试
应力
变形
soil mechanics
prestressed anchor cable
composite soil nailing
in-situ test
stress
deformation
