共查询到20条相似文献，搜索用时 265 毫秒
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龙伟民 《济南职业学院学报》2015,(3):99-101
通过室内承载板法和重复加载三轴试验研究1种典型黄土路基土在最佳含水量、3种压实度下的回弹特性,分析了动态回弹模量与强度指标室内CBR的相关关系。重复加载三轴试验方法采用参照AASHTO路基土与未处治粒料回弹模量试验方法的三轴重复加载试验方法。研究结果表明,黄土路基动态回弹模量和CBR均随着压实度的增加而增加,动态模量与CBR和压实度呈幂函数关系。 相似文献
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针对粉土填筑路基易存在的问题,分析了不同级配的土样的压实特性、不同击实功对压实性能的影响及含水量对于压缩指标的影响.试验表明:粉土的压实特性复杂;压实功增加到一定程度,粉土的最大干密度不再增加;含水量对于粉土的压缩指标影响较大.路基压实过程中要选择恰当的压实机具及压实遍数;严格控制含水量,尤其是控制填土的含水量不大于最佳含水量,以保证填土路基的稳定性. 相似文献
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曾玉莹 《长江工程职业技术学院学报》2011,28(2):1-4
以广东珠三角地区某场地砂土为研究对象,通过同时控制吸力、净室压力的非饱和土三轴剪切试验和同时控制吸力和净竖向压力的非饱和直剪试验,分析探讨了非饱和砂土的应力—应变性状及强度规律,得到了各自的变形和强度参数,并将这些参数进行了比较和分析,得出随吸力和净围压的变化,其强度、变形和各强度参数之间的变化规律。 相似文献
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通过对花岗岩进行动态三轴循环加卸载试验,研究花岗岩在围压条件下的疲劳损伤演化规律,发现其损伤变形过程可分为3个阶段,且岩石的侧向膨胀主导着疲劳损伤过程。同时通过分析围压条件对岩石疲劳损伤特性的影响规律。结果表明,围压和初始损伤对岩石疲劳寿命均有显著影响,揭示了当初始损伤一定时,岩石的疲劳寿命随围压增加而增长的规律。 相似文献
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通过对机场工程飞行区路基处理的试验,从碾压后的沉降量、压实度及碾压工效等方面对冲击压实技术与振动碾压技术进行比较,并对冲击压实成果进行载荷、反应模量和回弹模量等试验,证明冲击压实技术较传统的碾压技术压实效果好、压实工效高、技术可行,是一种值得推广的大面积填筑压实技术．同时,给出了针对此工程的冲击压实施：[参数． 相似文献
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侯凤健丁涵 《长江工程职业技术学院学报》2023,(2):14-17
最大干密度是路基和基层压实度确定的关键指标,不同试验方法影响着最大干密度的试验结果。选取4种路基或基层土样,分别通过击实试验和表面振动压实试验,对土样最大干密度的影响进行研究。研究表明:表面振动压实试验得到的最大干密度均大于击实试验得到的最大干密度,约为击实试验得到的最大干密度的1.03-1.09倍;随着土样最大粒径的增大,表面振动压实试验得到的最大干密度与击实试验得到的最大干密度均出现增长趋势,且增长趋势逐渐变缓;表面振动压实试验得到的最大干密度与击实试验得到的最大干密度比值随土样最大粒径的增大,出现先增加后减小的趋势。采用表面振动压实试验作为土样最大干密度的确定方法可以更为准确地反映路基和基层的压实质量。 相似文献
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研究目的:研制一种试验装置,以实现对非饱和土土-水特征曲线温度效应的有效测试。创新要点:1.研制了一种温控非饱和土三轴试验装置,包括加载系统、吸力控制系统和温度控制系统;2.利用研制的温控非饱和土三轴试验装置,对不同温度(25,40和60°C)以及不同应力(40,100和200 kPa)条件下的非饱和土土-水特征曲线进行了试验测定。研究方法:1.总结分析已有的温控三轴仪所采用的加热方式的优缺点,提出环向加热压力室内水体的方法;2.基于GDS非饱和土三轴仪,研制可实现温度控制功能的温控非饱和土三轴仪(图1、2);3.开展不同温度及不同应力条件下非饱和土土-水特征曲线的试验研究。重要结论:1.所研制的温控非饱和土三轴仪的实用效果得到验证;2.温度的升高将引起非饱和土持水性能的降低。 相似文献
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陈晋中 《雁北师范学院学报》2008,24(3)
低路基中,地下水因土壤基质对水分的吸力作用,导致路基土干湿状态发生变化,进而影响路基的强度及变形特性.路基土是非饱和土,其强度变化和变形特性需采用非饱和土理论解释.本文介绍毛细水作用下低路基强度和变形特性的主要研究成果. 相似文献
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通过对3个不同轴压比水准的预应力混凝土扁梁框架内节点试件的低周反复荷载加载试验,对试件的破坏形态、滞回曲线、延性、耗能能力等抗震性能进行初步研究,并判定轴压比对预应力混凝土扁梁框架内节点抗震性能的影响规律.试验结果表明,随着轴压比的增大,节点的抗震性能随之下降. 相似文献
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郑军锋 《福建工程学院学报》2019,(4):307-313
对新建兴泉铁路黄塘车站挤密螺纹桩复合地基的桩、土沉降及应力进行监测,分析了路堤荷载下桩、土沉降及差异沉降变化规律,桩土应力比与差异沉降关系。结果表明:桩、土沉降及差异沉降均随路堤填土高度的增加而呈线性增大;桩顶和桩间土应力随路堤填土高度的增加均不断增大,且桩顶应力大于桩间土应力;桩土应力比随着桩土差异沉降的增加先增加后减小,最终趋于稳定。结合修正的Terzaghi土拱理论提出了简化桩土应力比随桩土差异沉降变化曲线。现场试验分析结果有助于完善挤密螺纹桩复合地基设计理论,为工程实践提供一定的参考。 相似文献
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为了深入探究岩石物理力学性质,选取红砂岩作为试验材料,以冻融循环次数、围压作为研究指标,通过设计影响因素测试试验,探究这两项指标对岩石性能的影响。试验测试结果表明,围压、冻融循环次数两项影响因素对岩石的三轴抗压强度、弹性模量均有较大影响,力学性能变化显著。 相似文献
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ZHAN Liang-tong CHEN Ping NG C.W.W. 《浙江大学学报(A卷英文版)》2007,8(5):699-706
A laboratory study was carried out on both natural and compacted specimens to investigate the complex soil-water interaction in an unsaturated expansive clay. The laboratory study includes the measurement of soil-water characteristic curves, 1D free swelling tests, measurement of swelling pressure and shrinkage tests. The test results revealed that the air-entry value of the natural specimen was quite low due to cracks and fissures present. The hydraulic hysteresis of the natural specimen was relatively insignificant as compared with the compacted specimen. Within a suction range 0 to 500 kPa, a bilinear relationship between free swelling strain (or swelling pressure) and initial soil suction was observed for both the natural and compacted specimens. As a result of over-consolidation and secondary structures such as cementation and cracks, the natural specimens exhibited significant lower swelling (or swelling pressure) than the compacted specimen. The change of matric suction exerts a more significant effect on the water phase than on the soil skeleton for this expansive clay. 相似文献
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The use of loess as an earthen final cover material is promising in northwest China which has an arid and semi-arid climate. A full-scale testing facility with an area 30 m long by 20 m wide was constructed at the Xi’an landfill of municipal solid wastes to investigate the performance of an inclined capillary barrier cover. The cover consisted of a compacted loess layer underlain by a gravel layer. The testing facility was well instrumented for a gas permeation test and recording of the soil conditions in terms of volumetric water content, pore gas pressure, and soil temperature. Tests were performed to measure the gas permeability of the compacted loess before and after the planting of vegetation on the cover. The field measurements demonstrate that the capillary break at the fine/coarse soil interface allows the upper compacted loess layer to retain more water, and conversely reduces its gas permeability, which is favorable for reducing landfill gas emissions. When the degree of saturation of the compacted loess was greater than 85%, the gas permeability decreased significantly with a further increment in volumetric water content. The growth of vegetation roots tended to fill the large pores in the upper loosely-compacted loess, resulting in a decrease in gas permeability of one order of magnitude. The influence of soil clods in the compacted loess on gas permeability can be one to two orders of magnitude due to an increase in pore size and a decrease in tortuosity. 相似文献
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INTRODUCTIONSoftsoilsarewidelydistributedinChinasco-astalareas.The1985earthquakethatinflictedgreatdamagetoMexicoCitysitedonsoftsoilfounda-tionsgreatlyattractedattentionofresearchersandengineersandmovedthemtostudythedynamicpropertiesofsoftsoils.Manyresearcheshavebeendedicatedtothestudyofdynamicpropertiesofsoftsoils.InChina,deepcementmixingmethodshavebeenwidelyusedinthecoastalareas.Theme-chanicalpropertiesofthesecompositefoundationsoilsarenotthesameasthatofundisturbedsoftsoilsorotherkinds… 相似文献
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In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays. 相似文献
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Correlation of liquefaction resistance with shear wave velocity based on laboratory study using bender element 总被引：1，自引：0，他引：1
INTRODUCTION Evaluation of soil liquefaction resistance is an important aspect of geotechnical engineering practice, and several types of evaluating procedures have evolved over the last three decades. The well known “simplified procedure” originated by Seed and Idriss (1971) can be used to evaluate liquefaction resistance based on standard penetration test (SPT) blow counts. Over the years, the simplified procedure has been modified and updated with additional data, and has become th… 相似文献
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针对解决《土工试验方法标准》三轴试验中,黏性土抗剪强度指标出现的变异问题,提出一种黏性土试样组合方法,准确测定黏性土抗剪强度指标值在原有的一组相同物理性质(含水率,液塑限,级配)黏性土三轴试样的基础上,增加一组或两组相同物理性质试样,通过系统软件对试样进行完备组合,重新形成黏性土抗剪强度指标值样本基数,取其样本数的平均值为黏性土抗剪强度指标.通过试验验证了试样组合方法能有效避免三轴试验中出现的互不包容的莫尔圆,或黏聚力c出现负值试验结果,并在不增加试样数量的前提下,扩大了黏性土抗剪强度指标的样本基数,从而可准确测定抗剪强度指标值组合方法的提出为黏性土抗剪强度指标的测定提供一定的参考价值. 相似文献