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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 deformation characteristics of void rock foundation and karst cave filled concrete in karst area directly affect the internal stress and safe use of pylon and anchorage. The results of 30 rock-fill tests conducted on the Lushui Suspension Bridge show that the un-grouted rock mass is linear, upward convex, sickle-shaped and upper concave in the compression section, and the pressure p and the settlement s-curve are mainly concave. In the pressurized section, the ps curve is sickle-shaped and upper-concave, mainly sickle-shaped. In the springtime of the gap rock mass, after the pressure was relieved to the last 1 ~ 2 stage, the deformation hardly recovered and the pressure was completely removed , The deformation will be significantly reduced; the re-compression curve of the gap rock is concave, always below the compression curve, with a memory effect, the rebound curve is always below the rebound curve, and the rebound The curve of the concrete filled with karst cave is sickle-shaped and the recompression curve is concave. The springback and rebound curves are approximately parallel and horizontal before the pressure is completely relieved, and then compressed. The residual residual deformation rate of the rebound curve Smaller; cement slurry can effectively fill larger voids and caves, can not enter the micro-cracks in the closed rock; the current code on the final load of the final load of 1/3 as the bearing capacity of the void rock is feasible, corresponding to ps The end of the starting straight line segment on the curve is scaled Scheduled gap may be suited to rock; rock deformation modulus void under different pressure is varied. The results can provide the basis for evaluating grouting effect, design optimization and construction monitoring.