宁夏扬黄工程湿陷性黄土的工程处理实践与体会

湿陷性黄土地基浸水饱和后，由于易溶盐类的溶解，土结构的破坏，使其承栽力直线下降。宁夏扶贫扬黄工程大多位于湿陷性黄土地区，在地基处理过程中总结出了以下几点经验：①泵站地基可视湿陷土层的厚度不同．采用换填土垫层、砂石垫层，大直径扩底灌注桩或用预浸水法处理；②桥、涵、闸等建筑物应以换基、垫层和防护措施为主；③渠道地基应首先防止内水外渗，同时采取措施及时排除外水。

Practice of collapsible loess treatment in Ningxia Yanghuang Scheme

When the basement of collapsible loess is saturated by water, the earth structure is damaged due to the resolution of soluble salt, which causes the reduction of its bearing capacity. Ningxia Yanghuang Scheme is mostly located in collapsible loess area. Some experiences are accumulated for basement treatment. Firstly, regarding the depth of collapsible loess layer on the basement of the pumping station, the methods of changing earth-fill cushion or sand-rock cushion or application of large-diameter base-enlargement cast-in-place pile or pre-wetting treatment are adopted. Second, protection measures of changing basement or supporting layer for bridges, culverts and gates should be used. Third, seepage of internal water should be prevented for the basement of canal and measure should be taken for a timely discharge of outside water.