Triaxial Compression Deformation of Unsaturated Sericite Schist Residual Soil
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摘要: 为研究非饱和绢云母片岩残积土的三轴压缩特性,利用非饱和三轴蠕变仪,进行了控制基质吸力和净平均应力的压缩试验。试验结果表明:基质吸力相同时,随着净平均应力的增大,压缩变形逐渐变大;在一定范围内,随着基质吸力的增大,绢云母片岩残积土的屈服应力也增大,干密度较大时,屈服应力较大;净平均应力相同时,随着基质吸力的增大,变形逐渐减小。对比两种应力路径下的压缩试验,可以发现到达屈服吸力后,荷载的施加是产生变形的主要原因。Abstract: To study the triaxial compression characteristics of unsaturated sericite schist residual soil, the compression tests of controlling matric suction and net mean stress were carried out by using unsaturated triaxial creep apparatus. The results show that: when the matric suction is the same, the compression deformation increases with the increase of net mean stress. In a certain range, with the increase of matrix suction, the yield stress of sericite schist residual soil also increases, and when the dry density is high, the yield stress is high. When the net mean stress is the same, the deformation decreases with the increase of matrix suction. Comparing the compression tests under the two kinds of stress change, it can be found that the main reason for deformation is the application of load after reaching the yield suction.
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表 1 三轴压缩试验方案
试验方案 实验仪器 应力加载路径 控制基质吸力分别为0、50 kPa、100 kPa、200 kPa 非饱和
三轴
蠕变仪逐级施加竖向荷载,每级荷载下净平均应力应为25 kPa、50 kPa、100 kPa、150 kPa、200 kPa、250 kPa、300 kPa、400 kPa 控制净平均应力分别为0、100 kPa、200 kPa、400 kPa 25 kPa、50 kPa、100 kPa、150 kPa、200 kPa、250 kPa、300 kPa、350 kPa逐级施加基质吸力 表 2 不同基质吸力的各向等压压缩试验相关参数
基质吸力
s/kPa屈服平均
应力$ \overline p $/kPa${k_{\text{s} } }$ ${\lambda _{\rm{s}}}$ 屈服平均
应力$ \overline p $/kPa${ k_{\text{s} } }$ ${\lambda _{\rm{s}}}$ ${\rho _{\rm{d}}}$=1.95 g/cm3 ${\rho _{\rm{d} } }$=2.10 g/cm3 0 100 0.111 0.467 110 0.118 0.370 50 123 0.110 0.366 150 0.081 0.313 100 150 0.101 0.310 185 0.064 0.286 200 220 0.071 0.228 278 0.064 0.143 表 3 不同净平均应力的三轴压缩参数
基质吸力
s/kPa屈服
吸力$ \overline p $/kPa${ {{k} }_{\text{p} } }$ ${\lambda _{\rm{p} } }$ 屈服平均
应力$ \overline p $/kPa${ {{k} }_{\text{p} } }$ ${\lambda _{\rm{p} } }$ ${\rho_{\rm{d} } }$=1.95 g/cm3 ${\rho _{\rm{d}}}$=2.10 g/cm3 0 100 0.09 0.146 103 0.018 0.082 50 86 0.114 0.151 91 0.087 0.144 100 78 0.111 0.192 82 0.102 0.147 200 50 0.134 0.283 63 0.114 0.172 -
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