真空预压淤泥搅拌墙气密性试验分析与应用技术

通过淤泥搅拌桩墙的抗渗试验、工艺试验和现场试验，从土-水特性关系分析了真空预压期淤泥搅拌桩墙的抗渗时效性、抗渗能力及墙体的抗渗厚度，得出了淤泥搅拌墙在大面积真空预压工程中的共用密封墙桩帽技术及长短桩墙相结合等应用技术，可有效地解决共用密封墙的沉陷开裂和周边密封墙气密性的持久有效性问题。通过对广州南沙港区陆域吹填地基84×104 m2真空预压软基处理工程的应用，从预压期孔隙水压力、水位及真空度分布与变化情况，分析了密封墙气密性及真空预压的加固效果，分析表明：真空预压处理软土地基时，采用优化不透水淤泥搅拌墙方案进行密封处理是可行的。在85 kPa膜下真空度的情况下，1 m厚渗透系数小于10-6 cm/s的淤泥搅拌墙满足气密性的持久性要求。

Test study and application technique for airtight capacity of mixing silt wall under vacuum preloading

To study time-dependent airtight capacity, impermeability and breadth of mixing silt wall in vacuum preloading by soil-water character, comprehensive tests were carried out. It was found that mixing silt wall treated with pile cap at the intersection of two preloading areas and 2-rows’ inequilengthy pile wall using at the periphery was feasible to solve mixing silt wall subsiding and crazing and insure the durability of airtight capacity. A case study with large-scale area of 0.84 km2 is presented involving the hydraulic fill treated with vacuum preloading in Nansha Harbor; and airtight capacity of mixing silt wall and soil improving effects were analyzed by the distributing and changing in pore-water pressure, underground water table and vacuums; and it was concluded that mixing silt wall with breadth 1m and permeability less than 10-6 cm/s met the need of the airtight capacity under vacuum of 85 kPa.