DYNAMIC PRESTRAINING OF DRY SAND
DYNAMIC PRESTRAINING OF DRY SAND
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DOI：
10.1061/jsfeaq.0001398
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发表时间：
1970-03
期刊：
影响因子：
--
通讯作者：
V. Drnevich;F. E. Richart
中科院分区：
文献类型：
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作者：
V. Drnevich;F. E. Richart
动态预应变是在静态围压作用下，对土体施加振动剪应变。空心圆柱形渥太华砂试件，在扭转共振柱装置的测试表明，材料的行为可能会显着改变预应变。通常，在0.001%和0.01%之间的剪切应变下的预应变可以使动态剪切模量和阻尼加倍，显著降低静态压缩性，并且引起疲劳失效。密度变化不能解释这一点。当剪切应变小于0.001%时，预应变没有变化。这些影响取决于围压、孔隙比、剪应变幅值和振动周期。产生这些变化可能需要数百万个周期。试验结果表明，密度或孔隙比测量可能无法揭示振动荷载对干砂造成的这些参数的总体变化。这对于确定地基的动力响应和砂土的压实改良具有重要意义。
Dynamic prestraining is the application of vibratory shearing strains to soil that is acted upon by static confining pressure. Tests on hollow, cylindrical Ottawa sand specimens, in a torsional resonant column apparatus, demonstrate that material behavior may be significantly changed by prestraining. In general, prestraining at shearing strains between 0.001% and 0.01% can double the dynamic shear modulus and damping, strikingly reduce the static compressibility, and cause fatigue failures. Density changes cannot account for this. No changes occur for prestraining at shearing strains less than 0.001%. The effects are dependent on confining pressure, void ratio, shearing strain amplitude, and cycles of vibration. Millions of cycles may be necessary to produce these changes. Test results indicate that density or void ratio measurements may not reveal the total change in these parameters imparted to dry sands by vibratory loading. This is important in determining the dynamic response of foundations and the compaction improvement of sand soils.