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31.
Mechanical Behavior of a Clay Soil Reinforced with Nylon Fibers 总被引：2，自引：1，他引：1
A. R. Estabragh A. T. Bordbar A. A. Javadi 《Geotechnical and Geological Engineering》2011,29(5):899-908
Soft soils are well known for their low strength and high compressibility. Several techniques, including reinforcement, are
commonly used to increase the strength and decrease the deformation of this kind of soil. This paper presents the results
of an investigation into the effects of fiber on the consolidation and shear strength behavior of a clay soil reinforced with
nylon fibers. A series of one dimensional consolidation and triaxial tests were conducted on samples of unreinforced and reinforced
clay with different percentages of randomly distributed nylon fibers. The results show that the preconsolidation pressure
decreases and the coefficient of swelling and compression generally increase with increasing the fiber content. Furthermore,
the addition of the fiber leads to a significant increase in shear strength and friction angle of the natural soil. 相似文献
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The Jandagh–Moalleman road, which crosses the Great Kavir of Iran, was completed in 1999. Less than 1 year after completion,
road subsidence problems began. In order to determine the causes of failure, field observations were taken along with surface
and subsurface samples from road segments exhibiting typical problems. Laboratory experiments were conducted to determine
their physical, chemical, and engineering properties. The results indicate that there are two typical layers in this playa:
an upper, hard, salty crust layer composed of up to 46% soluble materials; and a lower, thick, muddy layer which is mostly
composed of silt, clay minerals, gypsum, and halite. It was concluded that mineral dissolution of the upper salt crust layer
and the sinking of road fill materials into the lower muddy layer, are the main causes of road settlement. An appropriate
method to protect the road against the dissolution of its soluble materials is recommended. 相似文献
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Banafsheh Sheikhipour Saman Javadi Mohammad Ebrahim Banihabib 《Environmental Earth Sciences》2018,77(19):712
In this study, a hybrid multiple criteria decision-making (HMCDM) model was proposed for prioritizing scenarios for managing groundwater use from an aquifer. Three scenarios, including the construction of subsurface dams, the use of artificial recharge and reducing groundwater use by 5% and 10% were considered to assess the most sustainable development approach. The examined MCDM models were: simple additive weighting (SAW); and MTAHP which is a hybridization of the modified TOPSIS and the analytic hierarchy process models. The criteria proposed for determining the order preference of the scenarios included the sustainable development index (IU) and a modified water exploitation index as well as economic, social and environmental indices. To assess the technical and economic impacts of the management scenarios, modeling of the aquifer was simulated for a 3-year period using these scenarios. The results of the assessment indicated that the scenario of water withdrawal reduction by 10% was the best scenario determined in MTAHP followed by a reduction in groundwater withdrawal by 5%, the use of artificial recharge and the construction of a subsurface dam, respectively. The difference between the results of MTAHP and SAW models was in their first and third ranks, in such a way artificial recharge scored the first rank in SAW model and the third rank in MTAHP model, also withdrawal reduction by 10% scored third rank in SAW model and first rank in MTAHP model. The results of these two models have demonstrated that the construction of a subsurface dam in Shahrekord aquifer is not an appropriate management option. According to the results of this study, MTAHP models can be applied for ranking feasible management scenarios in aquifers using the redefined sustainable development and modified groundwater exploitation indices introduced in this study. 相似文献
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This study examined the spatial-temporal variations in seismicity parameters for the September 10th, 2008 Qeshm earthquake in south Iran. To this aim, artificial neural networks and Adaptive Neural Fuzzy Inference System (ANFIS) were applied. The supervised Radial Basis Function (RBF) network and ANFIS model were implemented because they have shown the efficiency in classification and prediction problems. The eight seismicity parameters were calculated to analyze spatial and temporal seismicity pattern. The data preprocessing that included normalization and Principal Component Analysis (PCA) techniques was led before the data was fed into the RBF network and ANFIS model. Although the accuracy of RBF network and ANFIS model could be evaluated rather similar, the RBF exhibited a higher performance than the ANFIS for prediction of the epicenter area and time of occurrence of the 2008 Qeshm main shock. A proper training on the basis of RBF network and ANFIS model might adopt the physical understanding between seismic data and generate more effective results than conventional prediction approaches. The results of the present study indicated that the RBF neural networks and the ANFIS models could be suitable tools for accurate prediction of epicenteral area as well as time of occurrence of forthcoming strong earthquakes in active seismogenic areas. 相似文献
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A. R. Estabragh A. T. Bordbar A. A. Javadi 《Geotechnical and Geological Engineering》2013,31(2):501-510
This paper presents the results of an experimental investigation into the effects of discrete palm fibers on the consolidation and shear behavior of a randomly reinforced clay soil. Three groups of reinforced soil samples were prepared at three different fiber contents (10, 20 and 30 %). Consolidation and triaxial tests were carried out on the samples. The results indicate that the inclusion of the fiber reinforcement within the soil causes decrease in preconsolidation pressure and increase in compressibility and swelling indices. In addition, the strength and friction angle increase considerably in terms of total and effective stresses. The results also show that the increase in the slope of the critical state line in $ q :p^{\prime } $ space is a function of fiber content. 相似文献
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Saadat Samane Khalili Davar Kamgar-Haghighi Ali Akbar Zand-Parsa Shahrokh 《Natural Hazards》2013,69(3):1697-1720
Natural Hazards - Spatio-temporal patterns of seasonal streamflow droughts were investigated for the semi-arid Karkheh watershed, located in western Iran with an area of 41,470 km2,... 相似文献
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宽频介电常数频谱测井技术最近被引进石油工业.这种新技术区别于传统介电常数测井技术在于多频率频谱的测定和利用.高频谱端包含介质油水饱和度信息,而低频谱端对介质中孔隙结构和水的分布形态很敏感.这种新技术可以有效地被应用于比如超淡水介质或者超黏度重油等对于常规测井来说是很困难的测量环境,而且受介质水中的含盐度影响很小.随着井下测井仪器的投入使用,相应的实验室岩芯测定设备和方法就变得重要起来.因为实验室环境相对较为稳定和可控,实验室岩芯测量结果是对井下测量的很好地验证和校订.文献中记载了许多非破坏性的实验室介电常数的测量设备,然而这些设备的共同局限性是它们对岩芯尺寸和岩芯样本的要求和限制,一般要求粉末状岩芯或者一厘米左右的小柱状岩芯.在碳酸盐介质中,非均匀性和各项异性非常普遍,小的岩芯样本能否涵盖井下设备测量尺度(1.5英寸)的特性很值得商榷.本文中介绍了一种最新设计的实验室大直径宽频介电常数测量设备.这个设备可以直接测量石油工业传统的1.5英寸岩芯样本,测量是非毁坏性的,也就是测量后的岩芯样本可以直接用于其它实验室测量设备,比如电阻率测量或核磁共振测量等.大量重复性试验测得的介电常数色散频谱的精确度对于低损耗介质在2%以内而对于高损耗介质在对孔隙度和含盐度校正以后精确度在3%.文中详细介绍了测量设备所使用的反演程序的算法模型,以及反演误差的算法.反演最后的误差可以用来做数据质量的评定.该测量装置被用于许多物质的测定.测定物质的数据库中合成石英(fused quartz),Teflon,合成陶瓷以及单晶硅的介电常数值可以在文献中找到.该设备的测量结果与文献参考值相符合,说明了该设备测量结果的可靠性.该设备还测量了矿物晶体碳酸钙,晶体白云石以及晶体硬石膏的介电常数,这是常见的碳酸盐介质的主要成分.这些测量给出了碳酸盐介质的边界成分区域值作为参考.该设备测量的两个单晶硅柱状样本的介电常数频谱特性发现退火会改变晶体的结构提高强度,同时会改变介质介电常数的特性.同时矿物晶体碳酸钙测量值高于粉末状测量结果也说明晶体结构可能会导致介电常数测量的不同.该设备具有1.5英寸的大尺度,因此具有和井下设备相仿的测量范围,因而不受介质水平各项异性的影响.但另一方面,该设备仍可以研究垂直各项异性.垂直各项异性的主要原因可能是化学成分不同,孔隙结构不对称或者温度对水分布的影响等等.在对岩石地面露头采样的研究中,宽频介电常数频谱实验室设备检测出了岩芯垂直各项异性,通过对比核磁共振一维孔隙度剖面结构发现总孔隙度不均衡以及分布不对称为该各项异性的主要来源,并且被CT图像所证实. 相似文献
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Khezerlou Ali Akbar Amel Nasir Gregoire Michel Moayyed Mohsen Jahangiri Ahmad 《Mineralogy and Petrology》2017,111(6):865-885
Mineralogy and Petrology - The Plio-Quaternary alkaline volcanic rocks from the northwest of Marand (NW Iran) consist of trachy-andesites, trachy-basaltic andesites, leucite-tephrites and... 相似文献