New simplified method for calculating consolidation settlement of clayey soils exhibiting creep and its verification
-
摘要: 针对黏性土的固结与蠕变之间的关系,目前存在两个观点：假设A认为固结期间黏性土不会发生蠕变变形,蠕变变形发生在固结变形之后;假设B则认为黏性土的蠕变是土骨架的固有属性之一,它与固结变形同时发生。室内单元体试验结果和现场监测数据表明假设A常常低估了黏性土的总变形。然而,基于假设B的精确解常需要将土体弹黏塑性本构模型导入有限元软件才能进行固结沉降的分析,因而限制了该观点的应用。提出了一个考虑多级变荷载作用下蠕变与固结近似耦合分析的新简化方法。该简化方法具有形式简洁,参数明确的优点,可适用于黏性土的各种应力-应变状态和加载—卸载—再加载的复杂受力情况。选取瑞典的典型填筑工程,将新简化方法计算的沉降变形与有限元模拟结果、46 a的现场监测数据进行了对比分析,验证了新简化方法的正确性、精确性和广泛的应用范围。Abstract: There are two possible extreme opinions in terms of Hypotheses A and B: Hypothesis A assumes that creep occurs after the consolidation for both laboratory specimen and in-situ condition, whereas Hypothesis B assumes creep occurs during and after the “primary” consolidation. A new simplified method is proposed to calculate the consolidation settlement of clayey soils with creep subjected to the multi-staged ramp loading. The parameters of the new simplified method have the clear physical meanings, and it is easy to be used. With the help of the “equivalent time” concept, both normally consolidated state and over-consolidated state of clayey soils can be considered in the new simplified method. A typical project in Sweden was selected as a multilayered soil profile. The calculated results of the new simplified method offer a good estimation of the settlement by comparing with the results from the finite element analysis and 46 years’ recorded settlement data.
-
Keywords:
- new simplified method /
- settlement /
- finite element method /
- clayey soil /
- elastic visco-plasticity
-
[1] LADD C C, FOOTT R, ISHIHARA K, et al.Stress-deformation and strength characteristics. state-of the-art report[C]// Proc 9th Int Conf Soil Mech Found Engng. Tokyo, 1977, 2: 421-494. [2] YIN Jian-Hua, GRAHAM James.Elastic visco-plastic modelling of one-dimensional consolidation[J]. Géotechnique, 1996, 46(3): 515-527. [3] BJERRUM L.Engineering geology of Norwegian normally- consolidated marine clays as related to settlements of buildings[J]. Géotechnique, 1967, 17(2): 83-118. [4] 殷建华. 从本构模型研究到试验和光纤监测设备研发. 岩土工程学报, 2011, 33(1):1-15.
(YIN Jian-hua.From constitutive modeling to development of laboratory testing and optical fiber sensor monitoring technologies. Chinese Journal of Geotechnical Engineering, 2011, 33(1): 1-5. (in Chinese))[5] YIN Jian-Hua, FENG W Q.A new simplified method and its verification for calculation of consolidation settlement of a clayey soil with creep[J]. Canadian Geotechnical Journal, 2016, 54(3): 333-347. [6] FENG W Q, YIN J H.A new simplified Hypothesis B method for calculating consolidation settlements of double soil layers exhibiting creep[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2017, 41(6): 899-917. [7] ZHU Guo-fu, YIN Jian-hua.Consolidation of double soil layers under depth-dependent ramp load[J]. Géotechnique, 1999, 49(3): 415-421. [8] LARSSON R, MATTSSON H.Settlements and shear strength increase below embankments[R]. Geotechnical Institute Report, 2003: 63. [9] HOLTZ R D, BROMS, B.Long-term loading tests at Ska-Edeby, Sweden[C]// Proc of ASCE Spe Conf Perf of Earth Sup Structures. Lafayette, 1972: 273-284.
计量
- 文章访问数: 335
- HTML全文浏览量: 11
- PDF下载量: 212
下载:
