Dynamic Shear Behavior of a Needle-Punched Geosynthetic Clay Liner
Dynamic Shear Behavior of a Needle-Punched Geosynthetic Clay Liner
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DOI：
10.1061/(asce)1090-0241(2007)133:8(973
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发表时间：
2007-08
影响因子：
3.9
通讯作者：
C. Nye;P. Fox
中科院分区：
文献类型：
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作者：
C. Nye;P. Fox
本文对含水针刺土工合成材料粘土衬砌的动态内剪性能进行了试验研究。在单一正应力下进行单调和循环位移控制剪切试验，以研究位移速率、位移振幅、循环次数、频率和运动波形对材料响应的影响。单调剪切试验表明，峰值抗剪强度随位移速率的增大先增大后减小。循环剪切试验表明，循环响应主要受位移幅值控制。激励频率和波形对循环剪切行为或循环后静剪强度的影响不大。循环次数（大于或等于10次）对循环后静态剪切强度的影响也很小。剪切应力与剪切位移图显示的磁滞回线，大致类似于天然土壤的一些重要的差异，由于针刺钢筋的存在。割线剪切刚度随着位移幅度的增加而显著降低，随着持续循环而退化。阻尼比的值显着高于那些典型的天然粘土在较低的剪切应变水平。最后，随着位移幅度的增加，循环试验产生了逐渐降低的postcyclic静态峰值强度，由于更大程度的钢筋损坏。循环后静态剩余强度不受先前循环载荷的影响。
An experimental investigation of the dynamic internal shear behavior of a hydrated needle-punched geosynthetic clay liner is presented. Monotonic and cyclic displacement-controlled shear tests were conducted at a single normal stress to investigate the effects of displacement rate, displacement amplitude, number of cycles, frequency, and motion waveform on material response. Monotonic shear tests indicate that peak shear strength first increased and then decreased with increasing displacement rate. Cyclic shear tests indicate that cyclic response was primarily controlled by displacement amplitude. Excitation frequency and waveform had little effect on cyclic shear behavior or postcyclic static shear strength. Number of cycles (greater than or equal to 10) also had little effect on postcyclic static shear strength. Shear stress versus shear displacement diagrams displayed hysteresis loops that are broadly similar to those for natural soils with some important differences due to the presence of needle-punched reinforcement. Secant shear stiffness displayed strong reduction with increasing displacement amplitude and degradation with continued cycling. Values of damping ratio were significantly higher than those typical of natural clays at lower shear strain levels. Finally, cyclic tests with increasing displacement amplitude yielded progressively lower postcyclic static peak strengths due to greater levels of reinforcement damage. Postcyclic static residual strengths were unaffected by prior cyclic loading.