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表面活性剂随着工业、农业、日常生活等各种活动进入到土体及地下水中,不仅会带来环境污染的风险,还会改变土体的结构等从而影响土体的工程性质。为了合理评估表面活性剂污染土体的工程适宜性,采用阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和阳离子表面活性剂三甲基十六烷基溴化铵(CTAB)对粉土进行改性,通过直剪试验研究其对粉土强度特性的影响。结果表明,表面活性剂改性后的粉土内摩擦角减小,随着表面活性剂浓度的增大,内摩擦角减小的幅值越大,当表面活性剂浓度达2%时,粉土内摩擦角减小23.9%;SDBS改性后的粉土黏聚力大大减小,SDBS浓度为2%时,黏聚力减小91.8%,CTAB改性后粉土黏聚力增大,最大增幅达41.8%;改性粉土中加入不同p H的表面活性剂时,内摩擦角变化很小,表明表面活性剂的酸碱程度对土样内摩擦角影响较小,随着表面活性剂溶液p H的增大,改性粉土的黏聚力呈现出下降的趋势,p H改变了土壤的电荷的分配,改变了土粒间的静电作用,从而引起土体黏聚力的变化。
Surfactants enter into soil and groundwater with various activities such as industry, agriculture and daily life, which not only bring the risk of environmental pollution, but also change the structure of soil so as to affect the engineering properties of soil. In order to evaluate the engineering suitability of surfactant-contaminated soil reasonably, anionic surfactant sodium dodecylbenzenesulfonate (SDBS) and cationic surfactant trimethylhexadecylammonium bromide (CTAB) The soil is modified and its influence on the strength characteristics of silt is studied by direct shear test. The results showed that the internal friction angle of the modified silt decreased with the increase of the surfactant concentration, the larger the decrease of the internal friction angle was. When the surfactant concentration reached 2% The internal friction angle decreased by 23.9%; the cohesion of the silt modified by SDBS was greatly reduced; the cohesion decreased by 91.8% when the concentration of SDBS was 2%; the cohesion of silt increased after CTAB modification; The largest increase of 41.8%; modified silt with different p H surfactant, the internal friction angle changes very little, indicating that the degree of acid and alkali surfactants have little effect on the soil friction angle, with the surface activity Agent solution p H increases, the cohesion of modified silt shows a downward trend, p H changes the soil charge distribution, changing the electrostatic interaction between soil particles, causing changes in soil cohesion .