采用真空预压法处理公路软基滑塌的试验研究

Experimental study on the technique of vacuum preloading treatment of slides of soft soil foundations

以采用真空预压处理高速公路软基滑坡的工程实例为基础,通过原型观测和室内外土工试验,研究真空预压处理软基滑坡的施工工艺和处理效果,为了缩短施工时间,结合高速公路软基滑坡处治工程的特点,对铺膜方法、堆载时机等真空预压施工工艺进行改进。工程实践表明,改进后的真空预压法能在较短的时间内成功处理高速公路软基滑坡事故。滑坡处治过程中的侧向位移监测数据较清晰地反映了软基旧滑动带的分布范围和扩展过程,对此进行定量分析。侧向位移、孔隙水压力及地表沉降等监测数据均表明:真空预压可以有效控制旧滑动带的扩展和分布范围,进而控制软基的整体稳定性。室内外土工试验和工后沉降监测表明:在真空预压和堆载共同作用下,虽然经过前期预压的已滑软基土体的含水量降低较小,但是二者联合却能较明显地改善已滑软基土体的压缩性,进而降低工后沉降。真空预压是一种能快速处理软基滑坡的方法。

To investigate construction technique of vacuum preloading and the effects on the treatment of slide of soft soil foundations, a case study of a slide treated by vacuum preloading was conducted through in situ monitoring and geotechnical testing. Engineering practice shows that the improved vacuum preloading can deal with landslide successfully in a relatively short time. The distribution and expansion of the original slide zone was analyzed quantitatively by using lateral displacement monitoring data. Although the soil water content of the sliding soft foundation preloaded previously was reduced slightly after the vacuum treatment, the soft soil compressibility was significantly improved. It is concluded that the expansion of the slide zone could be restrained and thus the stability of the soft foundation could be controlled by vacuum preloading. The compressibility and settlement after construction could be improved significantly by combining vacuum and pile preloading.