摘要
Vacuum provides an alternative in reducing the length of preloading period for soft soil consolidation. In this method, soft clay foundation is preloaded by reducing the pore-water pressures through the application of vacuum pressure in combination with surcharge preloading. A full scale and fully instrumented test embankment was constructed. A drainage pattern system combined with 22 m prefabricated vertical drains (PVDs) length was used with triangular pattern of 1.2 m spacing. Among the foundation instrumentation, piezometers were installed in the foundation subsoil at varying depth to measure the pore-water pressures. After 6 months of vacuum pressure application at 80 kPa, the test embankments were raised to a maximum height of 5.5 m. The effect of vacuum preloading was investigated by the field conditions, maintaining higher vacuum pressures, and unloading vacuum. The results demonstrated the efficiency of combined vacuum and surcharge preloading.
真空荷载提供了一种减少堤坝软土地基固结时间的选择 .本文开展了一个海堤全断面的试验及原型观测研究 .试验堤高 5 .5m ,2 2m深且三角形布置的塑料排水板作为竖向排水通道 ,现场布置了水平测斜和沉降仪等观测仪器 ,埋设在不同地基深度的孔隙水压力计用来量测真空堆载联合荷载下的地基中超静孔隙水压力的变化 .通过场地条件分析、高真空度维持和真空卸载 ,得到了系统的沉降变形和孔隙水压力资料 ,试验结果验证了真空堆载联合预压加固海堤软土地基的效果 .
基金
TheNationalNaturalScienceFoundationofChina (No.5 0 3 790 10 )
