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Developemtnal Investigation of True Trizaial Testing Apparatus for Fynamic Soil Test

动土试验真三重试验仪的研制研究

基本信息

批准号：
60850098
负责人：
KITAMURA Ryosuke
金额：
$ 3.2万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1987
项目状态：
已结题

项目摘要

In 1985 the automatic measuring system of axial strains was developed for cyclic test vy the box type's treu triaxial testing apparatus. The capacitance type's wave heighr meter was made use of to measure the change of water level in the burette from which three axial strains in the orthogonal directions can be mesaured. It was found out that the strains couls be accurately measured by this system in the cyclic loading test. The automated data processing system also developed by using a microcoputer and the relations between stress and strain, excess pore water pressure and cyclic number, strains and cyclic number could be automatically drawn. The cyclic loading test on Toyoura sand was carried out under undrained condition in order to establish the system for the liquefaction test.In 1986 the cyclic loading rest on Toyoura sand with three different stress paths on II-plane were continuously carried out under the constant mnean total principal stress condition. It was found out that the difference of stress path in the cyclic loading peocess infulences the liwuefaction resistance. The test procedure and data processing system were modified to obtain the accurate test data.Shibushi Bay in Kagoshima and used for the cyclic loading test. Shirasu was divided into three different material by sieving, i.e., the first was composed of the soil particles whose diamter was smalleer than 2 mm, the second was 74-420 <micrn>m, and the third was 420-2000 <micrn>m. The second material whose grain size distribution is similar to one of Toyoura sand has the same liquegaction resistance as Toyoura sand. The thied material which is coarser than the second has lager liquefaction resistance than teh second. This fact is well-known for usaual sandy soil. On the other hand the first material which includes the finer grain than 74 <micrn>m has smaller liquercation resistance than teh second. This means that the fine grains in Shirasu make the liquefaction resistance of Shirasu small.

1985年研制了箱式三轴仪循环试验轴向应变自动测量系统。用电容式波高计测量滴定管中水位的变化，从而测量出三个正交方向的轴向应变。在循环加载试验中，该系统能够准确地测量应变。利用微机开发了数据自动处理系统，可自动绘制应力与应变、超静孔隙水压力与循环次数、应变与循环次数的关系。为了建立液化试验系统，对丰浦砂进行了不排水循环加载试验，并于1986年对丰浦砂进行了Ⅱ面三种不同应力路径的循环加载试验。结果表明，循环加载过程中应力路径的不同对液化抗力有影响。对试验程序和数据处理系统进行了改进，以获得准确的试验数据。通过筛分将白苏分成三种不同的材料，即，第一组粒径小于2 mm，第二组粒径为74-420 <micrn>m，第三组粒径为420-2000 <micrn>m。粒度分布与丰浦砂相似的第二种材料具有与丰浦砂相同的抗液化性。比第二种粗的第三种材料具有比第二种更大的抗液化能力。这一事实在通常的桑迪土壤中是众所周知的。另一方面，包括比74 μ m更细的晶粒的第一材料<micrn>具有比第二材料小的耐液化性。这意味着白砂中的细颗粒使白砂的抗液化性小。