真空预压与堆载预压加固软基的微观效果评价

Micro-structural effect evaluation of the consolidation for soft ground by vacuum preloading and surcharge preloading

本文以某高速公路路基软土为研究对象,在地质条件相近的、不同试验路段的软基加固方法(堆载预压、真空预压、真空-堆载联合预压)前后(加固时间达到3个月),工程单位分别进行了原位试验并采取软土样,开展了室内物理力学试验。结合工程单位所取的软土样进行了软土的微观结构试验,在试验的基础上,获得了软土在天然状态以及3种不同工况下的微结构图像,通过对图像处理得到加固前后的微结构特征参数。研究得出:在工程地质条件相近以及加固时间相同的情况下,无论是从宏观、微观结构,还是从固结过程和强度的增长上来看,3种工况的加固效果依次为:堆载预压→真空预压→真空-堆载联合预压。

A lot of soft soil samples are taken from the representative soft ground before and after the consolidation in certain expressway engineering. Based on the laboratory micro-structure tests and the field tests by using the different consolidation methods （surcharge preloading, vacuum preloading, vacuum-surcharge preloading）, the time of the consolidation tests lasts about 3 months. A great deal data from the soft soil about the micro-structural images and data in the natural state and after the overloading pre-compression state are obtained, and the effect evaluation of the different consolidation for the soft ground is presented. The study shows that under the same engineering geological condition and consolidation time, no matter what macroscopic and microscopic structures, or strength increase, the effect of the consolidation of the soft ground is in turn ： surcharge preloading →vacuum preloading→vacuum-surcharge preloading.