This paper describes a centrifuge study using a range of penetrometer tests (T-bar, piezocone and free-fall piezocone) to explore strength changes in a reconstituted, normally consolidated, natural calcareous silt. Various penetrometer test procedures were applied to measure the penetration resistances including monotonic, cyclic and twitch-type movements as well as pauses for pore pressure dissipation. These mobilised combinations of partial or full remoulding, strain softening, consolidation and viscous rate effects. The penetrometer resistance – representing a proxy for strength – reduced by a factor of 4·1 from drained to undrained conditions (at the lowest fully undrained penetration rate). In undrained conditions, viscous enhancement of the penetration resistance raised the tip and shaft resistance in free-fall piezocone tests by ∼2·8 and ∼3·6 times, respectively. The ‘restart’ resistance immediately after the dissipation tests was ∼2·5 times higher than the resistance prior to dissipation, giving an indication of consolidation-induced strength gain. The ‘twitch’ test (using sequential steps decreasing the velocity) captured drainage and viscous rate effects, and also gave a ‘restart’ resistance that showed even greater consolidation effects than from a dissipation test. Overall, the different penetrometer test types and procedures measured resistances in the same soil sample that varied by a factor exceeding 20 from highest to lowest, resulting from different penetration rates and history, due to strain rate, strain level (or remoulding) and consolidation. An expression for the monotonic penetration resistance combining drainage and viscous rate effects was fitted to the response of all tests, spanning >7 orders of magnitude in strain rate.

中文翻译：

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在钙质粉砂中进行渗透仪测试，以探索土壤强度的变化

本文介绍了使用一系列渗透计测试（T型杆，压电锥和自由落体压电锥）进行的离心机研究，以探索重构的，通常为固结的天然钙质粉砂的强度变化。各种渗透计测试程序用于测量渗透阻力，包括单调，循环和抽动型运动以及孔隙压力消散的停顿。这些动员的组合包括部分或完全重塑，应变软化，固结和粘性速率效应。渗透仪的电阻（代表强度）从排水到不排水（在最低的完全不排水渗透率下）降低了4·1倍。在不排水的情况下 渗透阻力的粘性增强使自由落体压电锥测试中的尖端和杆身阻力分别提高了约2·8和3·6倍。耗散测试后的“重启”电阻比耗散前的电阻高约2·5倍，这表明了固结引起的强度增加。“抽动”测试（使用连续步骤降低速度）捕获了排水和粘性速率的影响，并且还给出了“重新启动”阻力，与耗散测试相比，该阻力显示出更大的固结效果。总体而言，由于应变速率，应变水平（或重塑）和固结的不同，不同的渗透率和历史导致，不同的渗透仪测试类型和程序测量的同一土壤样品中的电阻从最高到最低变化超过20倍。