涵土沉降特征对涵洞外界面受力的影响

Influence of Culverts and Soil Settlement on Culverts Surface Stress

通过现场监测涵洞与周围填土的沉降、涵洞外界面受力,研究了涵土沉降特征及其对涵洞外界面受力的影响.结果表明：涵土差异沉降引起盖板涵顶中部和两侧墙顶土压力集中作用,在填土期间变化过程不同,涵顶土压力约为填土自重的1.4~3.0倍;涵土差异沉降使得涵顶对涵顶以上两侧土体竖向力的分担,涵侧竖向受力小于填土自重,涵洞侧墙受力远小于静止侧压力;受地基差异影响,涵洞沿横断面沉降不均,涵土之间发生被动土压力作用,引起涵洞两侧墙土压力和基底压力的非对称状态,以及基底压力骤然减小现象.

Through in-suit monitoring the settlement of culverts and soil and the stress of exterior surface of culverts,the characteristic of culverts and soil settlement and its influence to surface stress of culverts were studied. Theresults show that differential settlement between culverts and soil lead to concentration of vertical earthpressure on top of culverts,the changing process of the concentration on the middle part of top slab and on the bothsides of top slab are different. The measured vertical earth pressure is about 1.4 to 3.0 times the self-weight of thesoil. Due to the differential settlement between culverts and soil,the self-weight of the soil on both sides and abovethe culvert is shared by culverts,vertical earth pressure on both sides of culverts is smaller than the self-weight ofthe soil,so lateral earth pressure on side wall is smaller than static earth pressure. Because of the difference offoundation,culverts settlement distribute unevenly on cross section,and it leads to passive earth pressure betweenculverts and soil,earth pressure on side wall and foundation pressure distributed unevenly,and the suddenly reducephenomenon of foundation pressure.