软基深埋涵洞土压力和沉降的三维有限元分析

Analysis of earth pressure and settlement of culvert on soft foundation by 3-D FEM

通过软基坝下深埋涵洞的三维有限元计算,对涵洞的土压力及沉降问题进行了分析研究。研究结果表明:(1)在洞顶采用减荷措施时,洞顶竖向土压力明显减小,减荷效果比较显著;而对洞体的最大不均匀沉降率基本没有影响,涵洞周边土压力的分布特征与无减荷时也是相同的。(2)洞基处理深度变化对洞体附近的应力有影响,且随处理深度的增大,洞顶竖向土压力和洞侧面水平土压力分别有缓慢增大和缓慢减少的趋势。(3)洞底沉降随处理深度的增大而有微弱的减小,但不均匀沉降均小于0.5%,且从总体上看,其量值对工程的影响并无本质的差异,对洞基不进行处理时,洞基的不均匀沉降少许的增大不会对涵洞造成危害。

Based on 3-D FEM for the culvert under dam on the soft foundation,the earth pressure and settlement of the culvert are analysed.It is found that as follows:(1)When the reducing load measure is applied,the earth pressure distribution around the culvert and non-uniform settlement of bottom of the culvert are the same as without reducing load measure,but the vertical earth pressure reduce greatly which shows the effect of reducing load is obvious.(2)The variation of depth of the ground treatment has effect on stress around the culvert.The vertical earth pressure on the top of culvert slowly increases and the horizontal earth pressure at the side of culvert slowly reduces with the increase of depth of the ground treatment.(3)Although the settlement of the bottom of the culvert slowly decreases with increase of depth of the ground treatment,but the non-uniform settlement ratios are less than 0.5% which affecting the culvert are the same as each other.No treating the ground of the culvert,the danger is not produced with a few increase of the non-uniform settlement.