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Karst landscapes are widely distributed and different characteristics are displayed in different regions due to the effect of various natural environmental factors which occur throughout China.Buried karst cavern systems covered by sandy strata, which are widely distributed in Guangdong Province, possess the following features: high fissure water content, high rock permeability, susceptibility to collapse, variability in shape and an irregular distribution.When a shield tunnel is constructed in this kind of environment, hazards, such as sink holes, the ingress of water or stones, and damage to the constructed tunnels may occur.Thus; karst caves need to be treated before tunnel construction.Socket diaphragm walls are usually adopted to retain soil and to cut-off groundwater during deep excavations in Guangdong province, for the safety of the excavation and to reduce the impact on the surroundings.However, geohazards often occur during the construction of diaphragm walls in karst regions, causing problems such as diaphragm wall collapse, water or mud ingress, ground collapse and long-term instability.This paper presents a procedure for karst cave treatment to mitigate possible hazards during shield tunnelling in karst regions.The construction procedure includes field investigations, judgment, treatment, and effectiveness checks.