真空轻型井点地基处理试验研究

Experimental study of foundation treatment with vacuum well-point dewatering

为分析利用真空井点进行沿海软土地基处理的可行性,在天津汉沽区南部沿渤海区域某电厂建筑场地,布置了利用真空轻型井点抽水的现场地基固结试验,为分析其固结试验效果,试验过程中进行了地下水位、孔隙水压力的现场监测,试验前后安排了现场检测试验。抽水固结试验结束后,经试验前后的静力触探试验、十字板剪切试验及室内土工试验对比分析,证明加固效果显著。抽水试验开始后较短的时间（75d内）即可使加固的地基达到固结稳定,比贯入阻力提高200～300 kPa,十字板试验抗剪强度平均提高30～50 kPa,地基承载力可达120kPa。试验说明,采用真空轻型井点处理沿海浅部软土地基是可行的。

To analyze the feasibility of coastal soft soil foundation treatment using vacuum well-point dewatering, along the Bohai Sea region in the south of Tianjin Hangu district, a certain power plant construction site, a consolidation experiment is made by use of vacuum well-point pumping on site. In order to analyze the effect of consolidation test, groundwater level observation and pore water pressure test are all arranged and different depths of soil are tested before and after the test. After the comparative analysis of the data of static cone penetration test, vane shear test and soil test before and after dewatering, the results show that the consolidation effect is remarkable;a short period of time after the start of the pumping test （within 75 d）, the foundation can be reinforced to achieve the consolidation of stability;specific penetration resistance increased from 200 to 300 kPa;and average of vane shear strength increased from 30 to 50 kPa;foundation bearing capacity can be increased to 120 kPa. The consolidation tests show that, it is feasible in soft soil foundation treatment with vacuum well-point.