真空预压法处理拓宽路基边界效应影响分析

依托某深厚软土地区旧路提级扩建工程，以现场监测检测数据为基础，对采用真空预压法分幅处理新旧路基下伏软土时存在的问题进行研究。结果表明:当地基处理深度大于10.0 m时，狭长型真空预压区对边界外侧旧路面开裂影响范围在6.0～7.5 m之间，当加固深度增大时，影响范围并未随之增大；狭长型真空预压区横断面方向，路肩和路基中心沉降量相近，处理边界附近真空压力衰减不明显，边界位置地基处理效果良好；狭长型真空预压区对边界位置的黏土密封墙具有较好的加固效果，地基处理结束后，其强度可达到路基软土强度的85 %以上。

Analysis of Influence of Vacuum Preloading Method on Widening Subgrade Boundary Effect

In relation to an upgrading and expansion project of old roadbed in deep soft soil area, and on the basis of on-site monitoring and detection data, the existing problems in the treatment of soft soil under old and new roadbed by vacuum preloading method have been studied. The results show that when the depth of foundation treatment is greater than 10.0 m, the influence range of the narrow vacuum preloading zone on the crack of the old pavement outside the boundary is between 6.0 and 7.5 m, and the influence range does not increase with the increase of the reinforcement depth. In the cross-section direction of the narrow and long vacuum preloading zone, the settlement amount of the shoulder and the center of the roadbed is similar. The vacuum pressure attenuation near the treatment boundary is not obvious, and the foundation treatment effect at the boundary position is good. The narrow and long vacuum preloading zone has a good strengthening effect on the clay sealing wall at the boundary position. After the foundation treatment, its strength can reach more than 85 % of the strength of the soft soil of the roadbed.