关键词: 泥质弱胶结砂砾岩, 动力触探, 桩基承载力, 桩基静载试验

Abstract: The conglomerate in east Zhejiang is generally shallow deposited and has weak cementation.  The cored samples from the boreholes are usually in loose sand gravel shape. The geotechnical investigations are usually misclassified as sandy gravelly layer or completely weathered bedrock. This weakly cemented bedrock is usually assumed to have excessively low bearing capacity. The geotechnical properties of the weakly cemented conglomerate rock layer are evaluated and the axial capacity of piles into the type of bedrock is also studied. The results indicate that this cemented conglomerate can be classified as a soft rock. Although the cored samples are loose and have low recovery, the original strength of the rock could be high. The bedrock is moderately weathered and can be served as load bearing layer of the shallow foundations without strengthening. For the heavily loaded structures or structures with high deformation requirements, the post construction grouting or manually excavated enlarged base caisson can be used. Further, the construction technique should be improved and the rotary drilling machine is a better technique.

Key words: Argillaceous Weakly Cemented Conglomerate, Dynamic Penetration Test, Axial Capacity of Pile, Pile Static Loading Test