On the Volume Changes of Normally-Consolidated Clays
On the Volume Changes of Normally-Consolidated Clays
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常固结粘土的体积变化
DOI：
10.2472/jsms.12.264
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发表时间：
1963
期刊：
影响因子：
--
通讯作者：
T. Shibata
中科院分区：
文献类型：
--
作者：
T. Shibata
土的体积变化是正应力和剪应力变化的函数。体积变化的数学表达式的发展将有助于理解粘土的破坏准则，并允许更可靠的估计建立在块状粘土deposit.This本文介绍了一个正常固结粘土的应力-体积变化特性的调查。试验过程与排水压缩试验相似，不同之处在于加载的安排使平均主有效应力在整个试验过程中保持不变。D：粘性系数。V0：对应于σ 0 '的初始体积。ΔV：总体积变化。ΔVc：由于平均主应力的变化而引起的体积变化。ΔVd：由于剪切应力的变化而引起的体积变化。σ1' σ 3'：主有效应力。σ m '：平均主有效应力。σ 0 '：固结前压力。σc：临界应力，低于此值，粘性为零。σ m '-常数-试验人员：试验结果表明：1）正常固结粘土的体积随平均主有效应力的增大而减小，反之亦然;固结图的半对数图的原始分支通常是直的（图1），可以用公式ΔVc/V0=C·logσ m '/σ 0' 2表示。当正常固结的粘土受到剪应力的增加时，体积减小。图6示出了在σ m '-const.试验结果表明，ΔVd/（V0-ΔVc）是（σ1-σ3）/σm'的唯一函数，两者之间可以建立相关关系，ΔVd/（V0-ΔVc）=D{（σ1-σ3）-σc/σ m'} 3）正常固结粘土的总体积变化ΔV为ΔV=ΔVc+ΔVd，则ΔV/V0=C·logσ m '/σ 0'+ D（1-C·logσ m '/σ 0'）{（σ1-σ3）-σc/σ m'}
Changes in volume of soils are a function of changes both in normal stresses and shearing stresses. Development of mathematical expressions for the change in volume would be of aid for the understanding of the failure criteria for clays and would permit more reliable estimates for the settlement of structures founded on massive clay deposits.This paper describes an investigation of the stress-volume change characteristics of a normally-consolidated clay. The test procedure was similar to that in the case of drained compression test, except that the loading was arranged so that the mean principal effective stresses might be maintained constant throughout the test.The nomenclature used in this paper is as follows: C: coefficient of compressibility. D: coefficient of dilatancy. V0: initial volume corresponding to σ0'. ΔV: total volume change. ΔVc: change in volume due to the change in mean principal stress. ΔVd: change in volume due to the change in shearing stress. σ1' σ3': principal effective stress. σm': mean principal effective stress. σ0': pre-consolidation pressure. σc: critical stress, below which dilatancy is zero. σm'-const.-test: drained compression test in which the mean principal effective stress is maintained constant.The analysis of the test data shows that the volume change behaviour can be adequately described by the following conclusions:1) The volume of normally-consolidated clays decreases when the mean principal effective stress is increased, and vice versa. The virgin branch of a semi-logarithmic plot of the consolidation diagram is usually straight (Fig. 1) and can be expressed by the equationΔVc/V0=C·logσm'/σ0'2) The volume decreases when normally-consolidated clays are subjected to an increase in shearing stress. Fig. 6 shows that the volume change during a σm'-const.-test ΔVd/(V0-ΔVc) is a unique function of (σ1-σ3)/σm' and correlations between them can be established.ΔVd/(V0-ΔVc)=D{(σ1-σ3)-σc/σm'}3) The total volume change ΔV of normally-consolidated clays is ΔV=ΔVc+ΔVd, then ΔV is given by the expressionΔV/V0=C·logσm'/σ0'+D(1-C·logσm'/σ0'){(σ1-σ3)-σc/σm'}