昆明地区淤泥及淤泥质粘土地基振冲加固

Vibroflotation Compacting for Mud and Muddy Clay Foundation in Kunming Region

昆明地区淤泥及淤泥质粘土地基土层分为三种类型：一类是淤泥土层较薄，上面有硬壳层，下有强度较高的持力层；一类是淤泥土层厚度较大，上有强度较好的土层，下面土层强度较低；第三类是淤泥土层厚，上下土层强度均偏低．采用75kw振冲器对上述三类地基通过振冲碎石桩进行加固，均获得了满意效果．在加固后的地基上建成6～12层楼房计20余座，预估及评价淤泥地基振冲加固效果比较复杂，不仅与淤泥性质、土层厚度、地层结构、振冲器功率、施工工艺等因素有关，还与地基类型、荷载及分布有关．所以要依据碎石极承载力、硬壳土层作用、排水条件、基础类型及荷载条件等具体情况进行综合分析，这样才能正确评价振冲加固效果．

The mud and muddy clay foundations in kunming region can be divided into three types: (1) thiner muddy soil stratum with a duripan super-stratum and a stronger suport underlying stratum ; (2) thicker muddy soil stratum with a stronger overlylng and a wearer underlying soil strata;(3) thick muddy soil stratum with a lowerstrength overlying and underlying strata. These three types foundations were strengthened with stone piers by 75kW vibroflot, the satisfactory effect was gotten.The predication and valuation of the vibrofloation compacting effects in muddy foundations are com-plex, because it is in relationship not only with the mud property, thickness of soil strata, stratlgraphic structure, vibroflot power and construction method etc., but also with the type of foundation, load and its distribution. It is necessary to correctly valuate the effect of vibrofloation compacting, according to the concrete conditions such as bearing capacity of stone peirs, effect of duricrust stratum, drainage condition, type of foundation and load situation etc.