膨胀土加筋挡土墙现场试验研究与分析

Field study and analysis of reinforced earth wall for expansive soils

利用现场试验研究了膨胀土加筋挡土墙稳定性的影响因素。结果表明,在填筑高度较小的情况下,土压力增长较快,实测竖向土压力大于单位面积上的覆土质量,土压力系数逐渐增大;随着填土高度的增大,实测竖向土压力逐渐收敛并小于单位面积上的覆土质量,土压力系数也逐渐降低;降雨导致竖向土压力和侧向土压力均降低,但土压力系数增大,最大可达1.75。应变监测结果表明,膨胀土加筋挡土墙不会发生浅层滑坡,潜在的滑动面为深层楔形体;距面板1.5 m内外土体压实度不同不仅不利于筋带抗拉强度的发挥,而且会导致墙体产生较大的不均匀沉降,因此建议整个场地采用统一压实度。结合研究结果,最后对膨胀土加筋挡土墙的施工提出了有益的建议。

The field tests have been done in order to study factors which affect the stability of reinforced earth wall. The results show that earth pressure increases quickly and vertical earth pressure in situ is greater than soil weight of unit area and coefficient of earth pressure is gradually enhanced when the filling height is low. Along with the increase of filling height, vertical earth pressure is convergent and less than soil weight of unit area. In the mean time coefficient of earth pressure is gradually decreased. The rainfall decreases vertical earth pressure and lateral earth pressure,but coefficient of earth pressure increases. Reinforced earth wall would happen not in shallow coast but in deep wedgy coast according to strain results of reinforced strips. The compact degree for expansive soils within 1.5 meters should be consistent with outside, otherwise it would induce uneven settlement and reinforced would＇t be strips effective. At last some suggestions have been put forward for construction of reinforced expansive earth wall in situ.