Practical Use of Cone Penetration Test

(A)回顾了以往地震中砂土沉积的现场表现，重点介绍了静锥贯入试验qc值、细粒含量和平均粒度。根据循环应力比与归一化后的<q_(c1)> -值的相关性，表明：(1)<q_(c1)> -值大于150 kgf/ <cm^2>的洁净砂不会发生大面积的液化破坏，地震诱发应力比小于0.1的洁净砂，(2)细粒含量大于10%或平均粒径小于0.25 mm的洁净砂的抗液化能力明显高于相同qc-值的洁净砂。提出了临界归一化（<q_(c1)>）cr、临界（qc）cr、循环应力比、细粒含量和平均粒度等液化与非液化的经验关系。(B)在大型标定室中对松散饱和砂进行了一系列静锥贯入试验和新研制的振动锥贯入试验。观察了垂直应力、水平应力、渗透速率和多孔过滤器位置对超孔隙水压力、静锥阻力和振锥阻力的影响。将基于球腔膨胀理论计算的静压锥阻力与试验结果进行了比较，结果表明，静压锥阻力预测值与实测值吻合较好。并给出了地层学的评价，以及原位试验所得的循环应力比与抗振锥阻力的相关性。

(A) The field performance of sandy soil deposits during previous earthquakes was reviewed with emphasis on Static Cone Penetration Test qc-value, fines content and mean grain size. Based on the correlation between cyclic stress ratio and normalized <q_(c1)> -value, it was indicated that (1) extensive damage due to liquefaction would not occur for clean sands having <q_(c1)> -value greater than about 150 kgf/ <cm^2> and for the induced stress ratio due to earthquake less than 0.1, (2) sands containing more than 10 % fines or having mean grain size smaller than 0.25 mm show much greater in liquefaction resistance than clean sand having the same qc-value. Apart from that the empirical relationships separating liquefaction and non-liquefaction were proposed in terms of critical normalized ( <q_(c1)> )cr, critical (qc)cr, cyclic stress ratio, fines content and mean grain size.(B) A series of static cone penetration test and a newly developed vibro-cone penetration test were carried out on the loose saturated sand in a large calibration chamber. The effects of vertical stress, horizontal stress, rate of penetration and location of porous filter on the excess pore water pressure, static cone and vibro-cone resistance were observed. The static cone resistances estimated on the bases of spherical cavity expansion theory were compared with those from chamber test, and it could be seen that the predicted static cone resistance values agree well with observed one. The evaluation of soil stratigraphy and the correlations between cyclic stress ratio and vibro-cone resistance obtained from in-situ test were also presented.