高填方涵洞加筋减载的现场试验研究

在涵洞-填土相互作用机制基础上，分析了加筋桥减载法的减载机制。通过对高填方涵洞采用加筋桥减载措施的现场试验，研究了涵顶及格栅上、下垂直土压力的变化规律，分析了涵顶平面及格栅上、下土压力的分布和土压力系数随填土高度的变化规律。研究结果表明，加筋桥减载法通过涵顶内外土柱之间的摩擦和格栅的提兜效应将涵顶上方填土荷载向减载孔两侧填土上转移，可有效减小涵顶土压力，其减载效果与减载孔高度密切相关，减载孔高度越高，减载效果越显著。

Experimental study of high embankment culvert treated by imperfect ditch covered with a geogrid layer

Based on the culvert-filling collaborative working mechanism,load reduction mechanism of culvert treated by imperfect ditch covered with geogrid is analyzed.A field experiment on a high embankment culvert treated by an imperfect ditch covered with geogrid is conducted to study the variations of vertical earth pressure on the crown of the culvert and on the surfaces below and above the geogrid.The distributions of earth pressures on the crown of the culvert and on the geogrid,as well as the coefficients of earth pressure are studied.The results show that the vertical earth pressure can be efficiently reduced by the imperfect ditch covered with geogrid,the vertical earth pressure is reduced by the "membrane effect" of geogrid and the frictions on the surfaces between the central soil prism and the lateral soil prisms,which transfer the vertical pressure from the central prism to the lateral prisms.Its load reduction efficiency is closely related to the height of the load reduction ditch,and a higher ditch results in a lower vertical earth pressure.