关键词: 节理化岩体; 溶蚀作用; 风化; 工程特性; Hoek-Brown强度准则; 龙塘水库坝址;

Abstract: The dam foundation bedrock of the Longtang Reservoir is medium-thick layered limestone with developed joints and poor rock mass integrity, and belongs to typical karstic and jointed rock mass as the Karst-induced weathering generally occurs along the joints.Moreover, the rock mass dissolution and weathering degree presents an abnormal phenomenon that the river bed is stronger than the two river banks.Joint and Karst weathering are the key factors that affect the rock mass quality of the dam site.Based on the analysis of influences of Joints and Karst weathering on the rock mass, the in-situ test and the Hoek-Brown failure criterion were used to analyze the rock mechanical properties.And according to the rock strength, intactness index, structural surface characteristics and other indicators, the rock mass quality was comprehensively evaluated, and then the utilization and treatment measures were further determined.The results showed that:(1) The karstic and jointed rock mass were formed by structural rupture and dissolution action, which resulted in poor integrity, uneven and low overall strength.(2) Under the condition of confining pressure, the requirements of medium-height dam foundation could be satisfied, whereas the problems of inhomogeneous deformation of dam foundation still existed.(3) As the surrounding rocks of underground caverns, the karstic and jointed rock mass easily led to unstable blocks, collapse and deformation.The research results can be used as reference for similar projects.

Key words: jointed rock mass; Karst-induced weathering; weathering; engineering property; Hoek-Brown failure criterion; Longtang Reservoir dam foundation;