Vacuum preloading combined electroosmotic strengthening of ultra-soft soil

To assess the effectiveness of vacuum preloading combined electroosmotic strengthening of ultra-soft soil and study the mechanism of the process, a comprehensive experimental investigation was performed. A laboratory test cell was designed and applied to evaluate the vacuum preloading combined electroosmosis. Several factors were taken into consideration, including the directions of the electroosmotic current and water induced by vacuum preloading and the replenishment of groundwater from the surrounding area. The results indicate that electroosmosis together with vacuum preloading improve the soil strength greatly, with an increase of approximately 60%, and reduce the water content of the soil on the basis of consolidation of vacuum preloading, howeve~ further settlement is not obvious with only 1.7 mm. The reinforcement effect of vacuum preloading combined electroosmosis is better than that of electroosmosis after vacuum preloading. Elemental analysis using X-ray fluorescence proves that the soil strengthening during electroosmotic period in this work is mainly caused by electroosmosis-induced electrochemical reactions, the concentrations of Al2O3 in the VPCEO region increase by 2.2%, 1.5%, and 0.9% at the anode, the midpoint between the electrodes, and the cathode, respectively.     

无砂垫层真空预压法提高吹填淤泥地基承载力试验研究

本文结合温州吹填地基处理工程现场试验,对无砂垫层真空预压法在超软海底淤泥吹填的欠固结土的工艺和加固效果进行了研究,并对加固前后的土体物理力学特性变化进行了总结。结果表明,无砂垫层真空预压法在工艺上经济、可行,在加固效果上是有效的,可在类似工程中推广。     

无砂垫层真空预压法加固大面积软土地基的实例研究

结合温州民营经济科技产业基地丁山围垦区2标3#区37.32万m2吹填场区应用无砂垫层真空预压法进行软土地基处理的工程实例,介绍了无砂垫层真空预压的设计和施工过程。通过分析加固区表层沉降、孔隙水压力、静力触探试验、十字板剪切试验等实测数据,评价了其进行软土地基处理的加固效果,证明了无砂垫层真空预压法是一种加固大面积高压缩性软土地基的行之有效的方法,可以取得理想的加固效果。     

超声波提高微生物固化砂土效果的试验研究

为了研究超声波对巴氏生孢八叠球菌及其诱导碳酸钙沉积能力的影响,利用超声（20 kHz）开展超声辐照时间（0~30 min）和超声功率强度（0~0.8 W/cm³）的正交试验,用超声处理后的菌液进行水溶液试验和砂柱加固试验. 测定菌液脲酶活性、OD₆₀₀、细菌颗粒分布参数、碳酸钙的产量和加固后砂柱无侧限抗压强度. 分析超声辐照时间、超声功率强度、超声能量强度对碳酸钙产量的影响. 结果表明,超声辐照能够引发细菌产生生理强化反应,提高菌液脲酶活性. 当超声能量强度约为8 W·min/cm³时,超声辐照能够有效地提高菌液诱导生成碳酸钙的能力. 经优化的辐照策略（超声功率强度为0.4 W/cm³,处理时间为20 min）进行超声辐照处理后,水溶液中和砂柱中的碳酸钙产量分别提高了28.5%和35.6%,加固后砂样无侧限抗压强度为1.25 MPa,较对照组提高了91.6%.