基于数值分析不同填料下扶壁式挡墙土压力研究

Earth Pressure of Counterfort Retaining Wall with Different Fillings Based on the Numerical Analysis

不同填土情况下,运用Flac3D数值软件模拟了扶壁式挡墙侧向土压力分布情况,重点分析了砂土、黏土、多年冻土作为填料对侧向土压力分布的影响。结果表明：当砂土φ〉30°,作用于墙背上的侧向土压力将达到稳定;黏性填土φ值在15°-25°变化时,侧向土压力先变小后变大,并趋于稳定,当c〉20 k Pa时,墙背侧向土压力趋于稳定;多年冻土由于黏聚力大,改变φ、c,侧向土压力没有明显变化。另外,侧向土压力沿墙高缓慢增加,在底部出现回弯,与规范理论计算呈线性变化不一致,这主要是由于挡墙墙背、扶壁与填土的摩擦减压作用使计算结果小于理论值,作用于墙背上的侧向土压力比理论计算主动土压力小40%左右。

Lateral earth pressure distribution of counterfort retaining wall with different fillings was simulated on numerical software FLac3D with focus on the lateral earth pressure distribution with sand,clay and permafrost fillings. Results show that for sand, when φ 〉 30 degrees,lateral earth pressure exerted on the retaining wall in the horizontal direction tends to be stable;for clay, when φ is between 15 and 25 degrees,lateral earth pressure first decreases, then increases, and keeps stable with c 〉 20 kPa;for permafrost, due to its high cohesion, any change in φ and c causes no significant change in lateral earth pressure. In addition, lateral earth pressure slowly grows along the wall height with bending appearing at the bottom of the back, which is inconsistent with the linear change by the normative theoretical computing. This is mainly due to the pressure-decreasing friction between the retaining wall and fillings, which causes the calculation results less than the theoretical value：lateral earth pressure exerted on the counterfort retaining wall in the horizontal direction is about 40% less than the classical active earth pressure.