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1.
Study on mechanical behaviors of interface with cemented soil slurry between gravel and concrete by simple shear tests 
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下载免费PDF全文 The mechanical behaviors of the interface between coarse-grained soil and concrete are investigated by simple shear tests under conditions of cemented soil slurry (clay mixed with cement grout). The results show that the relation curve between shear stress and shear strain appears stress-strain softening and shear dilatation is significant. The point of peak strength and the position when the shear dilatation occurs are related to normal stress. In addition, shear dilatation occurs before the shear stress reaches peak value. In shear failure state, with the same height, the shear displacement increases as the normal stress increases. While with the same normal stress and at the same height, the shear displacement increases as the concrete content increases. A particle flow model of simple shear test between interface between coarse-grained soil and concrete is constructed by PFC (particle flow code). The disturbed height of the sample and the main influence factors are determined by analyzing the laws of particle motion at different heights inside the sample. The PFC results show disturbed height of the sample is related to maximum particle diameter of the soil, normal stress and roughness of the interface (with or without slurry) etc. In terms of the coarse-grained soil, the shear displacement is significant in the area which is close to the interface and about 3-4 times of the maximum particle diameter, and informed the obvious shear band. Further, the thickness of the interface can be regarded as the value. 相似文献
2.
《Soil Technology》1993,6(3):287-295
This study investigated the relationship between vane shear strength and moisture content for root-free and root-permeated sandy clay loam and clay soils, with a view to determining the effect of root density on the relationship. The results indicate that for both root-free and root-permeated soils, shear strength increases exponentially with decreasing moisture content. As expected, increases in root density considerably increase the magnitude of shear strength at all moisture contents investigated. In all cases, roots increased the magnitude of the shear strength of the clay soils much more than the sandy clay loam soils. Relative to the root-free soils, the roots increased shear strength in both soils by at least 500%. In the clay soils a higher relative increase of up to 850% is achieved in samples with a root density of 1.80 g cm−3. Also, relative to root-free soils, root permeated soils were found to exhibit a higher rate of shear strength increase with soil drying. This, it is suggested, is because of the higher shading effect of the shoots of the root-permeated samples leading to a slower rate of soil drying than in the root-free samples. 相似文献
3.
By using a simple shear apparatus that is developed from RMT-150B,a series of simple shear tests of interface between saturated sand and structure under high normal stress were carried out to study constitutive law and shearing stiffness of interface to provide some theoretical evidences for design and calculation of projects concerned with mechanical problem of interface.In test,sand was consolidated in upper shearing box firstly,then,shear was started and testing data was recorded under high and constant normal stress.During the process,sand can deform relatively freely.It is shown that the relation curve between shear stress and shear displacement under high normal stress in simple shear tests is different from that in direct shear tests,and the complete shearing deformation process of interface under high stress can be described as a nonlinear elastic-perfect plastic form;Weibull distribution with three parameters can overcome the mathematical deficiencies of hyperbola in NEPP.The new model which is established by substituting Weibull distribution for the hyperbola of NEPP better agrees with the testing data.The regressive results of the initial shearing stiffness demonstrate that the linear function is slightly better than power function to express the relation between the initial shearing stiffness and normal stress.Based on the new interface model,the formula of tangential shearing stiffness is proposed,meantime,the change trend of tangential shearing stiffness of the new model is compared with that of NEPP. 相似文献
4.
Combining the Mindlin elastic displacement solution with the elementary theory of finite element, in this paper, the shear stress distribution of pressure-dispersive anchor is calculated. Its work performances were compared with those of tensile anchor. According to the in-situ pull-out test of pressure-dispersive anchors in weak rock stratums, it is proven that the bearing capacity of pressure-dispersive anchor increases rather evidently than that of tensile anchor under the same condition and the effect of spacing between load-supporting bodies on the bearing capacity of pressure-dispersive anchor is analyzed. The analysis results of this paper can offer some references to the engineering application of this new type of anchor in the future. 相似文献
5.
为准确分析单箱双室组合箱梁的剪力滞效应，考虑钢混凝土的界面滑移效应和钢腹板的剪切变形，针对顶底板和翼板定义不同的剪力滞翘曲位移函数，基于能量变分法推导出单箱双室组合箱梁剪滞效应的控制微分方程及其闭合解。以单箱双室组合箱梁算例为基础，利用该方法分析其剪力滞效应的规律，结果表明：在同时考虑滑移和剪切变形时，组合箱梁的挠度比初等梁理论解大，且其挠度随界面滑移刚度的增大而减小；组合箱梁在均布荷载作用下，滑移量与荷载值近似成正比关系；在相同条件下，钢箱梁底板的剪力滞效应较混凝土顶板显著。 相似文献
6.
利用剪切流变试验对以水泥为固化剂的河道淤泥气泡混合轻质土的流变特性进行了试验研究。试验结果表明，经固化处理的河道淤泥气泡混合轻质土在荷载作用下具有类似于硬粘性土的流变特征。剪切流变可以分为3个阶段：在剪应力水平较低时，剪切流变曲线呈衰减稳定型；随着剪应力水平的提高，剪切流变曲线呈非稳定的等速型；当剪应力水平增大到一定程度时，剪切流变曲线呈加速型。河道淤泥气泡混合轻质土的流变性随着混合轻质土强度的提高而降低。根据试验所呈现的剪切流变规律，可以发现河道淤泥气泡混合轻质土的剪切流变符合七元件黏弹塑性剪切流变模型，模型能够比较好地描述河道淤泥混合轻质土在各种剪应力水平下的衰减、等速以及加速流变过程。 相似文献
7.
《Soil Technology》1993,6(4):321-327
As an alternative to the simple physical mixing of crushed lignite as an organic additive in soil restoration this study examined the potential benefits to structural stabilisation that might result from prior dispersion of the humic acid content in an alkaline aqueous slurry. When added to an unstable sandy loam topsoil, a clay loam subsoil and pure bentonite clay at a mixing ratio of 1:25, large increases in water stable aggregation were observed. However, additions at the same mixing ratio had no effect on the stability of two sandy mine waste materials or pulverised fuel ash. Because of the high application rates needed to alter aggregate stability, colloidal lignite was not considered to be useful as a substitute for more effective water soluble polymers. However, dispersion in aqueous ammonia prior to application could be used as a means of adsorbing humic materials on to clay mineral surfaces during the construction of synthetic topsoils. 相似文献
8.
依据现场大型剪切试验和室内直剪试验,研究了固结煤矸石的抗剪强度特性。试验剪应力-剪位移过程曲线表明,一定含水率条件下的固结煤矸石呈现明显的粘塑性体力学特性。以现场大型剪切试验煤矸石作为试样配料进行了室内直剪试验,分析了含水率和密实度对良好固结煤矸石试样剪应力-剪位移试验曲线以及抗剪强度参数的影响,在此基础上探讨了试样内煤及其它细颗粒的状态变化对固结煤矸石抗剪强度的弱化作用机理,最后对比分析了现场大型剪切试验抗剪强度参数值和室内直剪试验抗剪强度参数值的差异及其产生的主要原因。 相似文献
9.
A study which focuses on the role of matric suction in the stress strength of roadbed unsaturated soil was presented. Two types of tests were described, namely, the suction controlled shear test and microstructure scanned test. For the former, four sub tests were conducted under different suction and net normal stress conditions. And two unsaturated soil samples that belong to the same type but with different water contents were scanned. In contrast with clay soil, the corresponding results show that the strength of silty sand soil does not always increase as matric suction increases or soil water content decreases; there exists a peak contributed by matric suction that acts on soil stress strength. The main reason for this kind of phenomenon is due to the typical microstructure of this type of soil and the various types of pore water retention. Additionally, the state of stress in which soil sample meets can also exerts important influence on soil strength. 相似文献
10.
污水环境对水泥土力学性能的影响试验研究 总被引：1，自引：0，他引：1
由于多数地下水泥土工程直接与地下腐蚀性介质环境接触,必将导致水泥土材料的逐步劣化甚至失效破坏。以某市区工地附近明渠排放的污水作为侵蚀性介质,制作了不同水泥掺量的水泥土试件,通过对比试验,研究了污水环境和清水环境下不同水泥掺量、不同龄期的水泥土抗压强度和抗剪强度。结果表明,在污水或清水环境下,相同水泥掺量水泥土30 d龄期的抗压强度几乎相等,随着龄期的增加其抗压强度均逐步增大,但污水环境下其抗压强度增长的幅度明显小于清水环境,90 d后清水环境的水泥土抗压强度不再增长,而污水环境的抗压强度开始降低;污水环境和清水环境下的水泥土内摩擦角和黏聚力随龄期、水泥掺量的增加均逐步增大,污水环境下龄期90 d后的内摩擦角和黏聚力均开始降低。 相似文献
11.
Under the equipotential premise gradient, anode follow-up technical was proposed in the electro-osmosis reinforcement of soft clay. Eight electro-osmosis contrast tests were conducted through the experimental test. Currently, shear strength, displacement, moisture content, pH, conductivity of the soil and other indicators were monitored in the electro-osmosis test. Different electro-osmotic reinforcement effects were analyzed. The results show that: when the anode follow-up is used, the first anode follow-up can get a most significant effect. When the current density is high, arranging the anode follow-up will lead some extent reduce of the effect of the electro-osmosis, while the effect will be promoted when the current density is low. By carrying out the anode follow-up on the cathode region soil, a significant reinforcement effect can be obtained. Anode follow-up can reduce the resistance of the circuit in the anode region and effectively promote the electro-osmosis reinforcement effect. 相似文献
12.
桩-岩（土）接触面力学特性的研究是桩基承载机理研究的基础。通过红层泥岩桩岩接触面大型直剪试验，研究了红层泥岩桩岩接触面的力学特性，结果表明：接触面剪应力先随剪切位移增大而增大，在达到峰值后，剪应力随着剪切位移增大而降低，并最终趋于稳定值，应力应变曲线呈现出应变软化的特征。根据剪切试验结果，推导出桩岩接触面应变软化本构方程。利用fish语言对FLAC3D中自带的理想弹塑性接触单元进行二次开发，并应用开发的模型对桩岩接触面直剪试验进行了数值模拟，分析剪应力与剪切位移之间的关系，证明了该本构能够较好地模拟接触面间的应变软化特性。 相似文献
13.
钢筋混凝土无腹筋细长梁剪切破坏机理模型研究综述 总被引：1，自引：0，他引：1
根据现有关于钢筋混凝土无腹筋细长梁剪切破坏机理问题的研究成果,介绍了基于修正压力场理论的抗剪模型、临界剪切裂缝理论、塑性理论、压力路径理论、劈裂破坏理论和基于截面应变分析的抗剪模型的基本假设、核心观点及受剪承载力计算方法,并给出总结、归纳及评析;另一方面,利用相关试验数据和ACI-DAfStb无腹筋细长梁剪切破坏数据库,分别对不同理论模型的受剪承载力计算公式进行了设计参数的影响评估和统计评估;并展望了无腹筋细长梁剪切破坏机理研究的发展方向。研究结果表明：不同理论模型的部分假设缺少直接的试验依据支持,梁腹混凝土的受拉（劈裂）或受剪（骨料咬合）以及受压区混凝土对抵抗剪力的贡献成为抗剪机制的主要分歧;不同受剪承载力计算公式对不同影响因素的考虑方式的合理性和计算结果的准确度均有待进一步提高。后续深入研究应综合考虑剪切破坏问题的随机性和物理属性,利用先进测试技术、应力演化分析方法,进一步揭示剪切破坏机理。 相似文献
14.
Elastic-Perfectly Plastic Solution of Tunnel Surrounding Rocks Using Mogi-Coulomb Strength Criterion
Lyu Caizhong 《保鲜与加工》2014,(6):54-59
Reasonable choice of rock strength criteria is crucial for stress and displacement prediction and support design in tunnel engineering. Based on Mogi-Coulomb strength criterion and elastic-perfectly plastic model, analytical solutions of stress and displacement for surrounding rocks around a circular tunnel were derived The intermediate principal stress coefficient was used to present the intermediate principal stress effect. The results in this study were compared with the current solutions in the literatures and the influence of intermediate principal stress and shear strength parameters of surrounding rocks was discussed. The results showed extensive applicability and the Mohr-Coulomb strength criterion and Matsuoka-Nakai criterion are two special cases; when the intermediate principal stress coefficient b was equals to 0.5, the results indicated that the intermediate principal stress effect and its range for rock strength; the influence of cohesion and internal friction angle on the plastic radius and tunnel wall displacement was significant; Care should be taken to the effects of intermediate principal stress and shear strength parameter variations of surrounding rocks on tunnel design and construction. 相似文献
15.
This paper uses the combined bonding disc specimen, with a round end surfaces at both ends of the longitudinal adhesive joint and chamfered steel substrates hither, forms a shear stress distribution of uniform coefficient more than 0.97 and controls the normal tension stress along the bonding surfaces to a very low level. By means of the built-in high accuracy displacement measuring system of uniaxial INSTRON servo equipment, it eliminates the measuring system deformation from the measured total deformation, and then obtains the shear deformation of the joint, and eventually converts into the shear strain of the adhesive joint. The results of experiments using adhesive samples show that the bonding disc specimens are characterized by shear failure of the adhesive joint layers, so it can be thought that the method of combined bonding disc specimens can reveal the right shear properties of adhesives. The measured shear strength can be used as material strength criterion and the measured shear stress-strain relationship can be used in the load capacity analysis of bonded structural members. Because of the simplicity, the combined bonding disc specimen test method is suitable to be adopted in laboratories having displacement-controlled servo systems. 相似文献
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Accurate obtainting soil parameters of landslide is the key links for landslide stability evaluation and project management . This article takes Shennv Stream landslide in Chongqing Wushan County as an example, implementing unconsolidated and undrained shear test and mineral composition analysis by X ray diffraction for soil in different elevations of landslide ,conducting sensitivity test for various soil parameters of reservoir landslide change with different water level.Study shows that : Mineral composition of soil mainly contains Calcite, Quartz and clay mineral. Hydrophilic minerals in clay mineral have great effect on stability of landslide. Shear strength decreases by influence of water content on cohesion. Cohesion decreases sharply in a quadratic function relation with water content increasing .When water content comes to 18.21% ,change of cohesion tends to be stable.But the internal friction angle of landslide soil decreases linearly in small amplitude with an increase of water content. Research results may provide some important references for rationally choosing strength parameters of soil in similar landslide. 相似文献
18.
Single-lap-joint adhesively bonded metal specimen which is the national standard experimental method in use has an extremely non-uniform distribution of shear stresses along the joint, and tensile stress concentration of high values is produced on the steel substrate interfaces. Therefore the test result, which is not the real bonding shear strength between adhesive and steel substrates, can only be used as a test index for qualities of adhesives not the strength criterion for load is capacity evaluation. The combined bonding disc specimen is adopted for measuring bonding shear properties of adhesive on steel substrates, has a very uniform distribution of shear stresses in adhesive and along the bonding surfaces of steel substrates, of which the uniform coefficient is greater than 0.97. Furthermore, when adhesive joint is treated as an arc and steel substrates are chamfered at both ends of the joint, tensile stresses on the bonding surfaces can be reduced to less than 20 MPa which can hardly cause tensile failure. Thus, the results of combined bonding disc specimens can actually represent the real bonding shear strength or bonding shear-compression strength between adhesive and steel substrates, which can be used as strength criterion for load capacity evaluation of bonding members. 相似文献
19.
It is assumed that concrete compressive stress of the cross-section compression zone is linear distribution when the cross-section of high-strength concrete shear wall reaches yield situation. Based on the plane section assumption, the yield curvature formula of shear wall section is obtained by using moment - curvature analysis method. The parameters affecting yield curvature of high-strength concrete shear wall are studied by using the yield curvature formula. The results show that longitudinal reinforcement yield strain is the most vital factor of the yield curvature in addition to axial load ratio. When axial load ratio is larger, both wing walls of shear wall section have larger impact. The yield curvature formula is presented, considering the impact of axial load ratio, boundary reinforcement yield stress and both ends of wing walls of shear wall section based on the regression analysis of calculation results. On this basis, the vertex yield displacement formula of high-strength concrete shear wall is proposed, and the calculation results of formula correspond well to the vertex yield displacement experimental values of the 12 high-strength concrete cantilever wall. The formula is also suited for the vertex yield displacement of comment concrete shear wall. 相似文献
20.
Four series stud push-out specimens were conducted to study static mechanical behavior when stud shear connectors of composite beams were corroded. Firstly, the studs were manually rapidly corroded by electrochemical methods, and then a static load test was performed on them. Test results show that when corrosion occurs at stud rod especially close to combined surface, the ultimate bearing capacity reduces most by 18%, slip under the same load increases, and slip relative to the ultimate load reduces most by 12%. When corrosion occurs at the large end of stud, it has little effect on ultimate bearing capacity of push-out specimens, but deformation performance of stud shear connectors is affected seriously. 相似文献