共查询到17条相似文献，搜索用时 816 毫秒
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路堤下软土地基侧向位移与沉降关系分析研究 总被引：1，自引：0，他引：1
总结了软土地基下侧向位移的研究现状,从路堤中最大侧向位移和路中沉降之间的比例关系出发进行了分析研究。利用有限单元法,建立了路堤下软土地基的计算模型。计算结果表明,在路堤填筑期间最大侧向位移和路中沉降的增量大致相等,而在固结期两者的比例关系在0.14左右。不同的加载方式在数值上也有所不同。计算结果对路堤下地基侧向变形的计算分析具有一定的指导作用。 相似文献
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高填石路堤蠕变本构模型及其参数反演分析与应用 总被引：1，自引：0，他引：1
结合高填石路堤工后沉降变形机理与工程特点，基于工程实测数据，提出了高填石路堤工后沉降蠕变变形的双曲线型三参数本构模型，并引进遗传算法与有限元分析理论，建立了该模型参数的反演分析方法。在此基础上，利用蠕变有限元分析手段，深入探讨了高填石路堤工后沉降的分析计算方法，并开发了相应的分析计算软件。结合某高填石路堤工程实践，探讨了高填石路堤双曲线三参数蠕变本构模型和高填石路堤工后沉降计算的应用方法。工程实例分析表明，提出的本构模型及其工后沉降计算方法简单，可以满足工程要求，初步建立了一种新的高填石路堤工后沉降计算方法。 相似文献
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土石混合体填筑路堤中的非线性蠕变模型探析 总被引：2，自引：1，他引：1
针对土石混合体填筑路堤工后沉降的非线性蠕变特性,提出了一种能考虑材料非线性黏弹性变形的蠕变模型。基于目前对土石混合体蠕变机理研究,将路堤工后的蠕变沉降部分考虑为非线性的衰减蠕变过程,建立了修正的Kelvin模型、广义修正模型,且得到了模型参数的识别方法;通过对修正模型分析表明,非线性常数取值对蠕变曲线变化有较大影响,修正模型的蠕变长期应变值比Kelvin模型要小;结合相关文献中对土石体填料的蠕变试验研究资料,用修正Kelvin模型对试验结果进行拟合,并对参数进行了反演,反演效果良好。修正模型的建立可为编制非线性黏弹性数值计算软件提供理论基础。 相似文献
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土工格栅路堤加筋效果的影响因素分析 总被引：10，自引：0，他引：10
土工格栅作为一种新型的土工合成材料,由于具有高强度、低延伸率等特点而被选作主要的路堤加筋材料,在路堤中适当位置加入土工格栅能有效地减少路堤的沉降和侧向变形。本文采用通用非线性有限元程序ABAQUS分析了加筋前后的路堤底部的竖向位移、堤址点垂线下地基深度的水平位移和地表的水平位移,计算中采用D rucker-Prager模型和C lay p las-tic ity模型模拟土体的非线性,土工格栅采用一维杆单元来模拟。通过对加筋层数、筋材模量、软基模量、填土高度和软土层厚度等影响加筋效果的因素进行对比分析,从计算结果分析可知,路堤加筋虽然对软土地基的竖向位移影响不大,但加筋能有效抑制侧向位移的发展,这样增大了路堤边坡的稳定性,分析结果与大多数实际工程的实测资料相吻合。 相似文献
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有限单元法是计算基坑开挖支护结构变形的常见的数值计算方法,其土体模型参数的准确性是计算结果可靠性高的保证。邓肯- 张E-模型是岩土工程分析计算中常用的一种非线性弹性模型。本文以双排桩支护结构为例,针对模型参数敏感性进行大量非线性有限元计算,计算结果表明:影响基坑支护结构变形的主要参数为k、G、Rf和n,随着G、Rf和n的增大,侧向位移增大;随着k的增大,侧向位移减小。对于弯矩而言,参数的变化对弯矩的影响较小。从整体来看,邓肯- 张参数对侧向位移的敏感性要大于对弯矩的敏感性。 相似文献
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Correction of soil parameters in calculation of embankment settlement using a BP network back-analysis model 总被引：3，自引：0，他引：3
Finite element method (FEM) have been widely used for the calculation of settlement of embankment on soft soils in the last decade. However, due to the complexity of construction, spatial inhomogeneity of soils, as well as sensitivity of numerical results to the variation of soil parameters, large discrepancy typically exists between numerical outputs and field observations. This paper presents a novel method, combining FEM and an improved back-propagation (BP) neural network, for correction of soil parameters in numerical prediction of embankment settlement. Duncan–Chang hyperbolic soil model is adopted with the sensitivity of eight constitutive parameters numerically investigated. The soil parameters with large sensitivity are identified, and together with the representative settlements, are used for the training of the improved BP neural network which, once established, generates correction factors of soil parameters for subsequent more accurate FEM forward predictions. It is demonstrated that the proposed numerical back-analysis framework is very efficient in practical engineering applications to calculate highway settlement. 相似文献
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Tenfold cross validation artificial neural network modeling of the settlement behavior of a stone column under a highway embankment 总被引：1，自引：1，他引：0
Zamri Chik Qasim A. Aljanabi Anuar Kasa Mohd Raihan Taha 《Arabian Journal of Geosciences》2014,7(11):4877-4887
Construction of embankments in engineering structures on soft clay soils normally encounters problems related to excessive settlement issues. The conventional methods are inadequate to analyze and predict the surface settlement when the necessary parameters are difficult to determine in the field and in the laboratory. In this study, artificial neural network systems (ANNs) were used to predict settlement under embankment load using soft soil properties together with various geometric parameters as input for each stone column (SC) arrangement and embankment condition. Data from a highway project called Lebuhraya Pantai Timur2 in Terengganu, Malaysia, were investigated. The FEM package of Plaxis v8 program analysis was utilized. The actual angle of internal friction, spacing between SC, diameter of SC, length of SC, and height of embankment were used as the input parameters, and the settlement was used as the main output. Non cross validation (NCV) and tenfold cross validation (TFCV) were used to build the ANN model. The results of the TFCV model were more accurate than those of the NCV model. Comparisons made with the predictions of the Priebe model showed that the proposed TFCV model could provide better predictions than conventional methods. 相似文献
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准确预测路堤沉降对于规避风险和减小成本至关重要。传统的仅基于场地勘察数据的路堤沉降预测方法的预测值常偏离监测值。提出了基于贝叶斯理论的多源信息融合方法进行路堤沉降预测,采用有限元法模拟多层土体的固结沉降,并结合高效的马尔科夫链蒙特卡洛模拟法更新土体参数得到高维后验分布。以新南威尔士州的Ballina地区试验路堤数据为例说明了所提方法的有效性。结果表明,基于贝叶斯理论的多源信息融合方法可以有效融合勘察和监测数据,通过多源数据融合能够较准确地预测路堤沉降。对于Ballina路堤,总体上随着监测数据量的增加,路堤沉降预测预测精度逐渐提高。使用0～116 d监测数据可以准确地预测地表沉降;基于0～496 d监测数据可同时准确预测所有监测点的沉降。对于Ballina路堤,先验信息对沉降预测具有一定影响,但观测误差对预测准度影响微弱。 相似文献
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This paper investigates the settlement behaviour of a strip footing seating on the crest of an embankment and subjected to cyclic loading. The embankment fill is a dense sand and the issue is the gradual accumulation of settlement over a large number of load repetitions. Cyclic triaxial tests were first conducted to develop a consistent but simple material model for numerical implementation. Particular emphasis was placed on linking the stress-strain behaviour of an unload-reload cycle to the accumulation of permanent strain, with only five input parameters required to model the cyclic behaviour. The material model was implemented in a numerical analysis to compute the settlement behaviour obtained from model tests conducted by another researcher. It is pertinent to highlight that the same soil, compacted to same density at same moisture content, was used for both the cyclic triaxial tests and model tests. Reasonable to good agreement between the experimental and numerical results was achieved. 相似文献
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The mechanical behavior of natural clays is affected by their inherent anisotropy and metastable soil structure. A simple hierarchical model that considers initial anisotropy and destructuration was formulated within the framework of critical state soil mechanics. In the proposed model, stress sensitivity and a destructuration index were introduced to account for the degree of bonding and the rate of destructuration, respectively. An inclined yield surface was used to incorporate the effect of the initial anisotropy. The proposed model can be degenerated to the Modified Cam Clay model by setting the initial stress sensitivity equal to unity and using a horizontal yield surface. Reasonable agreement between the model simulations and the experimental results on a variety of stress paths demonstrated that the proposed model can capture well the deformation behavior of natural clay and reconstituted soil. The model was implemented into the finite element program for the numerical analysis of an embankment on soft clay improved with prefabricated vertical drains. The numerical predictions were compared with the field-measured data in terms of embankment settlement. Additionally, the numerical simulations were analyzed in terms of horizontal displacements, excess pore water pressure, mean effective stress and volumetric strain. All of the simulations and comparisons indicate the importance of considering the effects of plastic anisotropy, interparticle bonding and destructuration caused by loading beyond yield stress and field disturbance in analyzing the behavior of an embankment on natural soft clay. 相似文献
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Geosynthetic-reinforced and jet grout column-supported embankments on soft soils: Numerical analysis and parametric study 总被引：2，自引：0，他引：2
Using a computer code based on the finite element method, a study is conducted to analyse the time-dependent behaviour of a geosynthetic-reinforced and jet grout column-supported embankment on soft soils, as well as the influence of three factors: the embankment height, the elastic modulus of column and the column spacing. The cylindrical unit cell formulation is used. The numerical model incorporates the Biot consolidation theory with soil constitutive relations simulated by the p–q–θ critical state model. Special emphasis is given to the analysis of several parameters: settlement, excess pore pressure, effective stress, stress level, tension in the geosynthetic, soil arching effect and overall efficiency coefficient. 相似文献