| 强结构性对湛江黏土地区CPTU原位测定结果的影响 |
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| 引用本文： | 张先伟,孔令伟,郭爱国,拓勇飞.强结构性对湛江黏土地区CPTU原位测定结果的影响[J].工程力学,2013,30(2):118-124. |
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| 作者姓名： | 张先伟 孔令伟 郭爱国 拓勇飞 |
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| 作者单位： | (中国科学院武汉岩土力学研究所 岩土力学与工程国家重点实验室，武汉 430071) |
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| 基金项目： | 国家自然科学基金项目(51179186，41102200)；中国科学院岩土力学与工程国家重点实验室前沿探索性项目(SKLQ002) |
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| 摘 要： | 为了评价土的结构性对黏性土地区CPTU测试结果的影响。对湛江地区黏土(层)进行室内固结试验和CPTU原位试验，获得孔压静力触探响应特征，对比分析室内试验与CPTU测试结果求取固结系数的差异性。结果表明:湛江黏土的触探指标较高，qc=(2.5~3.0)MPa，Rf平均值约为1%；在强结构性黏土地区利用CPTU测定结果划分土层具有较高的准确性；受强结构性影响，土的埋深越大，CPTU的孔压消散时间越短，土的固结系数越大；浅层土试验孔压消散初期土体出现剪胀现象；利用室内试验得到湛江黏土在结构破坏前的固结系数Cv是重塑土的固结系数Cv的10倍左右；贯入过程中由于结构的破损会使探头周围土体的渗透性迅速降低出现指标失真，导致基于CPTU测试得到原状土的固结系数远小于室内试验结果；最后，考虑结构性，根据CPTU资料提出一个可用于估算结构性黏土固结系数的方法，该研究为准确获得结构性黏土地基处理设计参数提供了合理的科学依据。
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| 关 键 词： | 湛江黏土 强结构性 孔压静力触探 孔隙水压力 固结系数 |
EFFECT OF STRONG STRUCTURE ON CPTU TEST RESULTS OF ZHANJIANG CLAY AREA |
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| Affiliation: | (State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China) |
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| Abstract: | Laboratory consolidation test and CPTU test were conducted to test the effect of soil structure on CPTU test results of Zhanjiang clay area. To do that, response characteristic of CPTU was obtained and the difference between consolidation coefficients evaluated from consolidation test and CPTU test was comparatively analyzed. The results showed that penetration indexes of Zhanjiang clay were relatively high, for instance, qc=(2.5~3.0)MPa, and the average Rf was approximately 1%. High accuracy may be achieved in soil horizon division if CPTU test result was used in areas of strong structured clay. Affected by strong structure, the pore water pressure dissipation time decreased and consolidation coefficient increased with the increase of buried depth of soil. Shear dilatation appeared in the initial stage of pore water pressure dissipation during the test. The Cv evaluated from Zhanjiang clay before structure failure was approximately 10 times the value of the one from remolded soil in laboratory test. Permeability of soil mass around the probe reduced rapidly and index distortion was observed due to the structural damage during the penetration process, consequently, the Cv of undisturbed soil evaluated from CPTU test was much less than that from laboratory test. Taking structure into consideration, a method for estimating Cv of structured clay was proposed based on the CPTU data. The study provided a reasonable scientific basis for accurately obtaining design parameters of foundation treatment in structured clay. |
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