Abstract: 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.

Key words: rock mass with voids, concrete filled solution cave, vertical deformation behavior, plate loading test