强夯法治理湿陷性黄土地基的实践研究

Practice on treatment of collapsible loess foundation by dynamic consolidation method

宁夏交通厅在宁夏银川至武汉高速公路桃山口至同心段高速公路自重湿陷性黄土施工中采用强夯法消除了黄土的湿陷性,提高了地基承载力,并取得了大量的试验数据.根据对施工后自重湿陷性黄土地基的检测、评价、理论分析,总结了强夯法处理自重湿陷性黄土地基需要控制的几项指标:①采用1200 kN·m的能级进行强夯施工时,0—4 m范围内地基的湿陷性应全部消除;②0～3 m范围内的地基压实度>90％,地基沉降量>60 cm,最后二击平均夯沉量<5 cm.该试验结果已在同心至固原高速公路117 km,计1688 717 m2自重湿陷性黄土地基的施工中得到广泛的应用,取得了良好的效果.

Ningxia Communications Department decides to adopt dynamic consolidation method to deal with foundation in self-weight collapsible loess area on Yinchuan - Wu Expressway. Large amount of testing data has been obtained through dynamic consolidation method being adopted for treating self-weight collapsible loess foundation located in Taoshankou - Tongxin sections under Yinchuan - Wuhan Expressway in Ningxia, which eradicates collapsibility of loess and improves the foundation loading capacity. After the highway construction, according to testing, assessment, and theoretical analysis on self-weight collapsible loess, several controlling indexes which are required during the treatment of self-weight collapsible loess are summarized: (1) the collapsibility of foundation within 0 - 4 m range should be eradicated; (2) the compaction degree of foundation within 0 ~ 3 m is more than 90% , the settlement volume of foundation more than 60 cm and average settlement volume of final two punches less than 5 cm when adopting 1 200 kN· m energy level during dynamic consolidation construction. The summary provides reference in the field of highway design, construction and management in some degree. The testing result has been applied in self-weight collapsible loess foundation totalled up to 1 688717m2 under Tongxin - Guyuan Expressway with 117km in length and has obtained sound effect.