摘要
岩溶区空隙岩基和溶洞充填混凝土的变形特性直接影响索塔和锚碇的内部应力与安全使用。澧水特大悬索桥进行的30次岩基载荷试验结果表明,未注浆岩体在加压段,压力p与沉降s曲线呈直线型、上凸型、镰刀型和上凹型,以上凹型为主;注浆岩体在加压段,p-s曲线呈镰刀型和上凹型,以镰刀型为主;空隙岩体回弹段,卸压后到最后1～2级,变形几乎没有恢复,压力全部卸除后,变形才会明显减小;空隙岩体的再压缩曲线均为上凹形,总是处于压缩曲线的下方,具有记忆效应,再回弹曲线总是处于回弹曲线的下方,与回弹曲线近似平行;溶洞充填混凝土的压缩曲线呈镰刀型,再压缩曲线呈上凹型,回弹和再回弹曲线在压力全部卸除前近似平行且水平,再压缩、再回弹曲线的变形残余率较小;水泥浆液能有效充填较大空隙和溶洞,不能进入岩体闭合微裂隙中;现行规范关于终载压力的前级荷载的1/3作为空隙岩基承载力是可行的,对应于p-s曲线上起始直线段的终点为比例界限的规定可能不适应于空隙岩体;不同压力作用下的空隙岩体变形模量是变化的。研究结果可为评价注浆效果、设计优化和施工监控提供依据。
The normal deformation behavior of rock mass with voids and concrete filled solution cave in karst area influences directly the internal stress and safety of cable pylon and anchorage.There were thirty static load tests on rock foundation of Lishui River large suspension bridge.The results of study show that the pressurized p-s curves of natural rock mass look like main concave type,linear type,convex type and sickle type,but the one of grouted rock mass looks like main sickle type,concave type.In the rebound stage,the deformation of rock mass with voids doesn？t decrease significantly until all pressure or countdown level 1-2 is discharged.Located below the compression curve with memory effect,all re-compression curves of rock mass with voids look like concave type.Located below the rebound curve,re-rebound curves run approximately parallel to the rebound curve.For the concrete filled in solution cave,the compression curve looks like sickle type,the re-compression curve looks like concave type,the re-rebound curve runs approximately parallel-horizontal to the rebound curve;residual rate of deformation of re-compression and re-rebound curve is smaller than one.Cement slurry can fill effectively big voids and caves;but can not flow into closed microcracks of rock mass.The proportional limit determining method in the current codes may not meet rock mass with voids.With pressure changing,deformation modulus of rock mass with voids changes.The conclusions may provide the basis for grouting evaluation,design optimization and construction monitoring.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2011年第5期1309-1314,共6页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.50978036)
中国博士后科学基金资助项目(No.20070420818)
湖南省教育厅重点科研资助项目(No.09A005)
湖南省建设厅科研资助项目(No.湘建科[2008]459号-2)
关键词
空隙岩体
溶洞充填混凝土
竖向变形特性
岩基载荷试验
rock mass with voids
concrete filled solution cave
vertical deformation behavior
plate loading test
