Collapsible tests of loess under acid conditions and related sensitivity analysis
HU Zaiqiang1，2，ZHANG Yao1，3，YUE Wenqing4，SONG Zhaoyang1，XUE Ting1，HE Xinning1
(1. Civil Engineering and Architecture Institute，Xi?an University of Technology，Xi?an，Shaanxi 710048，China；
2. Shaanxi Key Laboratory of Loess Mechanics and Engineering，Xi?an University of Technology，Xi?an，Shaanxi 710048，China；3. Shaanxi Coalfield Geology Investigation Research Institute Corporation，Xi?an，Shaanxi 710021，China；
4. Shaanxi Environmental Protection Industry Group Co.，Ltd.，Xi?an，Shaanxi 710065，China)
Abstract：Cement connection of loess is an important intrinsic factor of loess collapse，which has the direct impact on the sensitivity of the collapse. In order to have a clearer understanding and to determine the sensitivity of loess collapse，the collapsible tests of loess in acid conditions were carried out to investigate the collapsible coefficient of loess，the stability time，the collapsible deformation rate and other sensitivity indexes of collapse under different pressures. The different concentrations of nitric acid were added to the immersion solution of distilled water. In addition，a scanning electron microscope(SEM) was used to detect the differences of the void space and structure of soil samples before and after the tests. The results show that the collapsible coefficient of the collapsible loess in the acid solution increases greatly under the low pressure，and that the stable time of the collapse is longer under all pressures. Loess collapsing has different ranges of pressure sensitivity in the distilled water and in the acid solution. The structural strength of the collapsible loess has the important influence on its embedded depth，etc. Two indexes that pertain to 90% of the finished time of collapse and the collapsible coefficient are utilized to evaluate the collapsible sensitivity of the loess and loess site. Chou Huang Canal，which collapsed before，is presented as a case study to demonstrate the application of this method. The results indicate that the collapsible sensitivity of the collapsible site is evaluated accurately with the proposed method.
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2017, Vol. 36 
