Abstract: The blocking effect of the suspended waterproof curtain can reduce the impact of foundation pit dewatering on the surrounding environment. However， the quantitative relationship between the insertion depth of the curtain and the land subsidence outside the pit is still unclear. Based on the principle of effective stress， and the partial coupling effect of the seepage field and the stress field where changes in soil void ratio and compression index caused by the drop of groundwater level was considered， a calculation method for land subsidence outside the pit caused by the dewatering of the foundation pit with suspended waterproof curtain in unconfined aquifers considering the relationship between the insertion depth of the waterproof curtain and the drop of groundwater level was proposed. A seepage experiment using a self-designed test model box was adopted to verify and analyze the proposed method. The results show that the calculated values are nearly close to the experimental values. The calculation method provides a significant reference for land subsidence prediction and the design of the insertion depth of rational waterproof curtain.

Key words: suspended waterproof curtain; foundation pit dewatering; land subsidence; seepage; liquid-solid coupling