碎石桩复合地基现场试验及数值模拟分析          下载免费PDF全文

许崇华 《江苏地质》2013,37(4):668-674

依托某储油罐的碎石桩复合地基处理实例,进行了复合地基现场变形、荷载传递及固结速率的长期监测。参照工程实际建立了碎石桩复合地基三维有限元水土耦合分析模型,讨论了碎石桩桩长以及复合地基置换率对碎石桩复合地基工程性状的影响。监测结果和有限元数值分析结果表明：碎石桩复合地基对于沉降和水平位移的控制效果较好,保证了施工过程中地基的稳定性;随着上部荷载的增加,桩土应力比逐渐增大。碎石桩给地基提供了良好的排水通道,有效加快了地基的固结速率;碎石桩复合地基沉降随着桩长和置换率的增加而减小,但达到一定程度时,置换率和桩长对沉降的减少效果有限;复合地基桩土应力比随着桩长的增加而增大,随着置换率的增大而减小;置换率和桩长的增加都能加快碎石桩复合地基的固结速率,但是置换率对固结速率的影响更大一些。  相似文献   

变形监测技术在上海复兴东路越江隧道中的应用     

段志强  康海珍 《北京测绘》2013,(3):32-36

为及时了解越江隧道沉降形变特征,分析越江隧道交通形变及损坏成因,并为越江隧道交通安全运营、预警及结构分析提供数据支持,此文通过2012年5月对越江隧道进行第4次沉降监测和收敛监测,结果显示目前越江隧道没有出现异常。  相似文献   

发电厂建（构）筑物沉降监测数据分析     

肖天雄 《华南地震》2012,(2):99-103

发电厂设备较多,结构复杂,危险性较大,必须对其建（构）筑物进行沉降和变形监测。以湛江奥里油发电厂为例,在沉降观测的过程中,根据各个建筑物的沉降情况,进行了沉降趋势分析,针对湛江奥里油电厂建筑物沉降的特点,提出发电厂在建设（包括减载）及运营期间应按设计或相关规范要求,对建筑物及其周围进行沉降监测,以便掌握建筑物的沉降现状和规律,对发电厂的安全运营具有重要的参考价值。  相似文献   

高速公路高填方路基沉降量的神经网络预测   总被引：4，自引：2，他引：2  

王祥秋杨林德  高文华陈秋南 《工程地质学报》2004,12(4):427-430

利用BP神经网络较强的高次非线性映射能力和学习功能 ,建立了基于人工神经网络的高速公路路基沉降量的预测模型。该模型依据现场实测资料 ,避免了计算过程中各种人为因素的影响。通过对某高速公路高填方路基沉降量的现场监测成果的学习与预测检验 ,证明其预测精度与适用性良好 ,具有较大的工程实用价值  相似文献   

Interactive effects of hypoxia and PBDE on larval settlement of a marine benthic polychaete     

Paul K.S. Shin  Singaram Gopalakrishnan  Alice K.Y. Chan  P.Y. Qian  Rudolf S.S. Wu 《Marine pollution bulletin》2014

Marine benthic polychaete Capitella sp. I is widely known to adapt to polluted habitats; however, its response to xenobiotics under hypoxic conditions has been rarely studied. This research aimed to test the hypothesis that interactive effects of hypoxia and congener BDE-47 of polybrominated diphenyl ethers (PBDE), which is ubiquitous in marine sediments, may alter the settlement of Capitella sp. I. Our results revealed that under hypoxic condition, settlement success and growth in body length of Capitella larvae were significantly reduced compared to those under normoxia of similar BDE-47 concentration. While no significant changes in morphology of settled larvae were noted in both exposure conditions, the presence of BDE-47 could enhance polychaete growth. The present findings demonstrated that the interactive effects of hypoxia and environmentally realistic concentrations of BDE-47 in sediments could affect polychaete settlement, which, in turn, reduce its recruitment and subsequent population size in the marine benthic ecosystem.  相似文献   

Application of a memory surface model to predict whole-life settlements of a sliding foundation     

《Computers and Geotechnics》2017

In this paper a novel modelling procedure is proposed to estimate whole-life settlements of tolerably mobile sliding foundations. A new kinematic hardening-critical state-state parameter constitutive model, the Memory Surface Hardening model, is implemented in a one-dimensional analysis to predict accumulated vertical settlements under drained lateral cyclic loading. The Memory Surface Hardening model performance is compared with the Modified Cam Clay and Severn-Trent Sand models. The Memory Surface Hardening model is adopted to simulate available experimental data from centrifuge tests to predict the settlement of a sliding foundation at the final stable state (i.e. no further volume changes occur).  相似文献   

Finite element modeling of the consolidation behavior of multi-column supported road embankment     

Sari W. Abusharar  Jun-Jie Zheng  Bao-Guo Chen 《Computers and Geotechnics》2009

A multi-column composite foundation is a new concept utilizing different column types with varying lengths and diameters to support the embankment fill and to mobilize the strength and stiffness of the soil at shallow depths. This study presents the results of finite element analyses using the finite element software PLAXIS to investigate the consolidation behavior of a road embankment constructed on a multi-column composite foundation. The finite element results are calibrated for a period of 200 days. The settlement, horizontal displacement, differential settlement, column axial force, and the development and dissipation of excess pore pressure are presented and discussed in detail. It is concluded that a multi-column composite foundation allows a fast rate of consolidation and significantly increases the embankment stability. A multi-column composite foundation formed by CFG–lime columns is more effective than one formed by SC–lime columns. The CFG–lime columns improve the long-term stability of the embankment because the compression modulus of CFG columns is significantly greater than that of SC columns.  相似文献   

太行山区河谷内居民点的特征及其分布格局的研究--以河北省阜平县为例   总被引：21，自引：0，他引：21  

王成  武红  徐化成  郑均宝  周怀军 《地理科学》2001,21(2):170-176

以河北省阜平县的5条河流主流河谷为案例，全面分析了河谷内居民点的斑块特征和分布格局，表明，河谷内的居民点位置基本是在的向阳一侧靠近坡脚的地方，一般以狭长形状为主；居民点面积在河谷面积中所占的比例在各个河段的变化很大，但不同河流居民点面积占河谷面积的比例十分接近，在10%-17%的范围内变支。在研究区内，河段内居民点的面积与河谷面积、河谷内农田面积是呈正相关的，表明本地区河谷内的居民对河谷土地具有很强的依赖性；河谷内的居民点增加使河谷林木急剧减少，但居民点内部和周围的河谷林木为其安全性、舒适性提供了保障。  相似文献   

Consolidation behavior of a soft mud treated with small cement content   总被引：1，自引：0，他引：1  

Tao-Wei Feng  Jia-Yih Lee  Yi-Jiuan Lee 《Engineering Geology》2001,59(3-4):327-335

Soft mud can be found in many large size reclaimed lands. Such soils present extremely high settlement potential that needs to be alleviated by means of effective ground improvement techniques. Current knowledge on applying small cement content to reduce settlement potential of soft mud is limited. This study concerns the consolidation behavior and settlement potential of soft mud treated with small cement content. Based on the pH values of soft mud–cement mixtures, oedometer specimens with cement content of 6% were prepared for consolidation tests. The test results show that preconsolidation pressure is rapidly developed and secondary compression is reduced. The ratio of secondary compression index to compression index is also reduced, indicating a change in grain size characteristics. The coefficient of consolidation is increased for consolidation pressures smaller than the preconsolidation pressure. This indicates that treating the soft mud with a small cement content can be very effective for reducing settlements in cases where new loads are small to medium and the time for ground improvement is limited.  相似文献   

Foundation settlement statistics via finite element analysis   总被引：5，自引：0，他引：5  

A. Nour  A. Slimani  N. Laouami 《Computers and Geotechnics》2002,29(8):641-672

The dispersion observed in soil data comes both from the spatial variability which greatly influences the behavior of large structures and from errors in testing. Thus, the geotechnical engineering deals with uncertainties for which deterministic approaches are not suitable. The resort to probabilistic techniques, enables modeling uncertainties by analyzing their dispersion effect on the global behavior of the structure. The scope of this paper is analyzing settlement and differential settlement variability of a pair of foundations on random heterogeneous medium. The random soil properties of interest are the elastic modulus, and the Poisson ratio. The elastic modulus is modeled as a spatially random field by adopting the lognormal distribution, which enables analyzing its large variability. Because soil Poisson ratio is bounded in practice between two extreme values, its random field is obtained by using the Beta distribution. In this study, one proposes for the Beta field determination, a mapping technique on the probability distribution function diagram, by solving a non-linear equation. However, the mean and variance are unchanged through the mapping operation. Because the soil Poisson ratio is a positive parameter, one prefers to perform the mapping operation with the probability function of the lognormal distribution. Also, the proposed technique can be used for other bounded soil properties such as the porosity. In this paper, settlement and differential settlement statistics prediction are carried out using Monte Carlo simulations combined with deterministic finite element method (DFEM). A performed parametric study shows the following: (i) as the variability of the elastic modulus increases as settlement and differential settlement statistics are important, also, settlement statistics decreases as the Poisson ratio variability increases, and differential settlement statistics do not seem be affected by its variability. (ii) settlement and differential settlement statistics are important for positive inter-property correlation. (iii) a great influence of the correlation lengths on settlement and differential settlement statistics.  相似文献