关键词: 双排桩, 深基坑, 坑内留土, 被动区土压力, 有限元数值分析, 前排桩, 后排桩

Abstract: To investigate the evolution of horizontal shift, bending moment and passive earth pressure of the retaining structure with double-row piles, finite element analysis was conducted to analyze parameters including earth berm size, reinforcement effect and elastic modulus. Results suggest that: 1) increasing the width and height of earth berm could both reduce the horizontal shift and bending moment, and increasing the height of earth berm has better effects; 2) reinforcing the earth berm could remarkably reduce the horizontal shift of the double-row pile; 3) elastic modulus of earth berm over 80 MPa has little effect on the decrease of horizontal shift; 4) further increment of the width of earth berm after reaching a threshold has slight impact on improving the earth pressure in passive zone. The conclusion is applied in the Capital Land Shopping Mall at Gutian, and had great economic returns and social benefits. In addition, hardening of the earth berm is an effective measure to avoid platform instability in the construction caused by rainwater soaking. Proper surcharge on the earth berm is an effective way to improve the earth pressure in passive zone, beneficial for controlling the horizontal shift of double row piles.

Key words: double row pile, deep foundation pit, earth berm, passive earth pressure, finite element analysis, front row pile, back row pile