察尔汗地区复合地基加固盐渍土效果试验

Experiment study on reinforcement effect of composite foundation in saline soils of Qarhan region

采用动力触探试验和平板荷载试验,就砾石桩、强夯、强夯置换和冲击碾压4种方法对盐湖区察格高速公路盐渍土地基的加固效果,从桩体密实度、复合地基承载力、变形模量、桩土应力比等方面进行了分析.结果表明:①强夯置换墩的密实度低于砾石桩;②强夯置换加固效果最好,冲击碾压法效果最差,承载力两者相差166.9%;③夯击能是后3种加固工艺中决定加固效果的重要指标,其大小直接关系着加固后的承载力和变形模量的数值;④砾石桩桩土应力比约为3.36,强夯置换复合地基墩土应力比为2.05,砾石桩和强夯置换均可有效降低盐渍土天然地基的沉降.

Using SPT and slab loading test, the paper analyzed different reinforcement effects from four different reinforcement technologies-gravel piles method, dynamic compaction method, dynamic consolidation, dynamic replacement method and impact compacted method for Cha-Ge highway saline soils ground located in salt lake area, and got the following conclusions： ①The density of dynamic consolidation and dynamic replacement is lower than gravel piles of saline soils. ②Dynamic consolidation and dynamic replacement method has the best reinforcement effect, and impact compacted method has the worst. The gap is 166.9 %. ③Tamping energy is important on reinforcement effect to the last three methods and it is related directly to the values of the strengthened bearing capacity and deformation modulus. ④The stress ratio of the pile and the soil between the piles is about 3.36, while the one of composite foundation for dynamic consolidation and dynamic replacement is about 2.05. Both technologies mentioned above are useful on reducing the settlement of natural saline soils foundation.