分级真空预压联合电渗和强夯法试验

真空预压联合电渗法是疏浚淤泥最有效的地基处理方法之一，但由于真空预压阶段排水板淤堵导致土体固结不足，同时电渗阶段土体开裂严重导致界面电阻较大、能耗过高，该方法在实际工程中并未得到广泛应用。基于此提出一种新的方法，即分级真空预压联合电渗和强夯法，以克服原方法存在的缺陷；同时研究在不同真空分级级数下分级真空预压联合电渗和强夯法对疏浚淤泥的加固效果。采用自制玻璃模型桶，通过室内模型试验对疏浚淤泥加固过程中的土体出流量、电流强度、土体表面沉降以及试验后土体含水量、土体十字板剪切强度、土体pH值和阳极腐蚀量等进行监测。试验结果表明：在分级真空预压、电渗、强夯联合作用中，采用分级施加真空压力的方式有效缓解了真空预压阶段排水板淤堵，使得土体出流强于真空预压联合电渗法，土体表面沉降发展更显著；在电渗阶段与强夯结合有效提高了土体致密性，弥补了土体裂缝，增强了电路电流，提高了电渗排水效率；采用分级真空预压联合电渗和强夯法较传统真空预压联合电渗法而言阳极腐蚀量更小，能耗更低；真空分级级数越多，对疏浚淤泥的加固效果越好；在试验中采用分3级施加真空压力的方式处理疏浚淤泥，处理后的土体十字板剪切强度达到105 kPa，含水量降至37.6%，对疏浚淤泥的加固效果最优。

Experiment on Hierarchical Vacuum Preloading Combined with Electro-osmosis and Dynamic Compaction

Vacuum preloading, in combination with electro-osmosis, is a useful ground improvement method for dredged slurries. However, due to the insufficient consolidation of soil caused by drainage plate clogging during the vacuum preloading stage and the high interface resistance and high energy consumption caused by severe soil cracking during the electro-osmosis stage, this method is not widely used in practice. In this study, a new method of hierarchical vacuum preloading combined with electro-osmosis and dynamic compaction is proposed to overcome these drawbacks. In addition, the consolidation effect of the hierarchical vacuum preloading combined with electro-osmosis and dynamic compaction on a dredged slurry under different vacuum grading levels was investigated. The laboratory model tests were conducted in a self-made glass bucket model, and the parameters of the dredged slurry, such as soil drainage, circuit current, soil surface settlement, after-test vane shear strength, water content, pH, and mass of anode corroded in the reinforcement, were monitored. The test results show that for the combined action of hierarchical vacuum preloading, electro-osmosis, and dynamic compaction, the method of applying the vacuum pressure through grading effectively alleviates the clogging of the drainage plate during the vacuum preloading stage. In this case, the soil drainage exceeds that of vacuum preloading combined with electro-osmosis, and the development of soil surface settlement is more significant. Furthermore, the combination of dynamic compaction during the electro-osmosis stage effectively improves soil compactness, compensates for soil cracks, and enhances the circuit current, improving the electro-osmotic drainage efficiency. Moreover, in comparison with the traditional vacuum preloading combined with electro-osmosis, the hierarchical vacuum preloading combined with both electro-osmosis and dynamic compaction shows less anodic corrosion and lower energy consumption. In addition, the more the vacuum pressure classifications, the better the reinforcement effect on the dredged slurry. By applying the vacuum pressure in three stages to treat dredged slurry, the vane shear strength of soil after treatment reaches 105 kPa, the water content in the soil decreases to 37.7%, and the optimal improvement effect of dredged slurry can be achieved.