Pb(Ⅱ)污染土抗剪强度及电阻率特性研究

Study on Shear Strength and Electrical Resistivity of Pb(Ⅱ) Contaminated Soil

通过研究不同铅污染含量在快剪试验中的抗剪强度和电阻率的变化,探讨了剪应力和剪切位移、抗剪强度和铅污染含量、电阻率和剪切位移及抗剪强度和电阻率的关系。结果表明:铅污染土在剪切过程中没有明显的屈服点,剪应力随剪切位移的增加而增大;受铅污染土壤抗剪强度略大于未污染土壤;铅污染土壤的抗剪强度在5 mg/kg时比未污染土壤大,之后随污染浓度呈现先减小后增大的趋势;电流频率为低频(50 Hz)和高频(50 kHz)时,电阻率随剪切位移变化趋势相同,均先减小后增大,在4 mm左右最小,但50 k Hz时的电阻率曲线更光滑,更能有效地反映铅污染土在剪切破坏的过程中电阻率变化情况,采用电流频率为50 kHz的电阻率能较好地判断铅污染土的剪切破坏位移。

By studying the shear strength and electrical resistivity of contaminated by Pb in different pollution conten,the relationship between shear stress and shear displacement,shear strength and pollution content,electrical resistivity and shear displacement,shear strength and electrical resistivity were discussed. The results showed that with the displacement increasing,the shear strength increased all through; shear strength of contaminated soil was slightly larger than uncontaminated soil; at 5 mg / kg of pollution content,shear strength of contaminated soil was larger than uncontaminated soil,after that shear strength decreasing at first then increasing; in low current frequency（ 50 Hz） and high current frequency（ 50 k Hz）,the change between electrical resistivity and shear displacement have the same trend,with shear displacement decreasing,the electrical resistivity increased and minimum at about 4 mm,but electrical resistivity curve of 50 k Hz is smoother than 50 Hz,to effectively reflect the changes in electrical resistivity of contaminated soil during shear process,so using current frequency of 50 k Hz can better judge shear fracture displacement of contaminated soil.