西江特大桥岩锚锚碇的承载特性研究  

Bearing behavior of rock anchorage system for west river bridge construction

作　　者：刘秀敏[1] 陈从新[1] 肖国峰[1] 鲁祖德[1] 王永卫[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室,武汉430071

出　　处：《岩土力学》2013年第1期196-202,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.10872207)

摘　　要：针对西江特大桥广州岸岩锚锚碇系统的承载稳定性问题,采用工程地质勘察、室内及现场原位岩石力学特性试验、钻孔摄像及声波测试等手段,获取承载边坡的岩体地质力学特性,并建立边坡地质力学模型,同时进行现场拉锚试验验证预应力锚索设计的可靠性。采用三维数值模拟方法研究锚碇系统在施加预应力和承担外荷载两种情况下,边坡岩体的稳定性和锚碇群锚中不同位置的预应力锚索锚固力的分布特征。研究表明,在桥梁施工荷载的拉拔作用下,广州岸锚碇边坡整体稳定,坡表变形为毫米级;锚索锚固力呈不均匀分布形态,主要集中在锚固段前2 m范围内,最大值出现在锚固段端头;锚碇群锚的锚固力应力集中程度由大到小依次是角锚、边锚、中间锚。超载试验表明,整个锚碇系统的极限抗拔力不小于8倍设计荷载。锚索现场监测数值显示,锚碇承载期间锚索索力基本稳定,中间锚的索力小于角锚。研究方法及成果可供类似的桥梁及抗倾拔工程中的岩锚锚碇设计及安全评价借鉴。Aiming at the bearing capacity of rock anchorages for West River Bridge construction on Guangzhou bank slope,the engineering geological investigation,indoor and in-situ rock mechanical tests,borehole camera,sound wave tests,etc.are carried out to gain the rock mass geomechanical characteristics and the slope’s geomechanical model.Then anchorage tests are carried out to confirm the reliability of prestressed cables in-situ.The three dimensional numerical simulation is used to research the stability of the wall rock around anchorages when group cables prestressed and bearing load,as well as the distribution rule of prestressed cables’ resistance arranged at different positions in an anchorage.The results indicate that the rock anchorage system is stable when the West River bridge constructed and the displacements of the slope’s surface keep mm level;the prestressed cables’ anchoring force turn out uneven distribution and mainly concentrate in 2 m scope on the front of anchoring section;in the prestressed cable group of one rock anchorage,the concentration degree of cable resistance is first the angle cable,next the side cable,last the middle cable which from a large to small in turn.The overload experiments show that the rock anchorage system＇s ultimate anti-pullout capacity is not smaller than 8 times of the designed pulling load.Prestressed cables’ monitoring indicates that the axial force of cable is just stable during the whole period when the construction load increasing;and the middle cable’s axial force is less than the angle cable’s one.The research methods and results can be for reference in similar bridge constructions and anti-pullout projects.

关 键 词：岩质边坡 锚碇 预应力锚索 锚固力 数值模拟 

分 类 号：TU443[建筑科学—岩土工程]