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自1982年以来,我们在杭州市深厚软土地区的三个场地进行了石灰桩加固软弱地基的试验研究。 11台底板尺寸为2×2m的载荷板试验和静力触探、十字板及钻孔取土等室内外试验结果证明,石灰桩对加固杂填土和软粘土地基均有明显效果。石灰桩可使淤泥质土的含水量和孔隙比明显降低,并使淤泥质粘土的十字板抗剪强度cu提高到原来的1.13～4.50倍;对杂填土地基其加固效果更加显著(载荷试验表明,地基容许承载力可提高到原来的1.58～4.14倍)。 石灰桩已首次在上述地区的三幢六层住宅工程中应用。孔隙水压力、压力盒、磁性分层沉降仪和长期沉降观测表明,建筑物沉降均匀、工作性能良好。 本文还根据八项典型工程的调查,给出了杭州深厚软土地区住宅地基常用处埋方法的技术经济分析结果。对比分析表明,在相同地质条件下,采用石灰桩可比钢筋混凝土预制桩和混凝土灌注桩节约基础费用40～60％左右。
Since 1982, we have carried out experimental research on the reinforcement of soft ground by lime piles at three sites in the deep soft soil area of Hangzhou. The results of indoor and outdoor tests of 11 baseplates with dimensions of 2×2m for load plates, static penetration tests, cross-slabs, and drilled soils have proved that limestone piles have obvious effects on the reinforcement of miscellaneous fill and soft clay foundations. Lime piles can significantly reduce the water content and void ratio of muddy soil, and increase the cross-plate shear strength cu of muddy clay to 1.13-4.50 times; the consolidation effect of miscellaneous landfills is more pronounced (load test It shows that the allowable bearing capacity of the foundation can be increased to the original 1.58-4.14 times). Lime piles have been used for the first time in three six-storey residential projects in the above areas. The pore water pressure, pressure box, magnetic layered sedimentation instrument and long-term settlement observation indicate that the building has uniform settlement and good work performance. Based on the investigation of eight typical projects, this paper also gives the technical and economic analysis results of common buried methods for residential foundations in deep soft soil area in Hangzhou. Comparative analysis shows that, under the same geological conditions, the use of lime piles can save about 40 to 60% of the basic cost compared with reinforced concrete prefabricated piles and concrete cast-in-place piles.