共查询到20条相似文献,搜索用时 15 毫秒
1.
加筋尾矿砂的连续增强区 总被引:2,自引:0,他引:2
为研究土工织物增强尾矿砂结构的变形、破坏机理 ,室内进行了不同铺设层数下的三轴剪切试验。试验结果表明 :当仅铺设一层土工织物时 ,试件的变形、破坏特征和纯尾矿砂相似 ;随着土工织物铺设层数的增加 ,试件中均出现数个水平连续增强区域 ,抑制剪切变形的进一步发展。试件达到峰值强度后 ,仍有较高的承载能力。最后探讨了连续增强区对加筋土结构强度增长的影响 相似文献
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加筋土结构中筋材的变形模量和布筋方向对其补强作用的影响 总被引:3,自引:0,他引:3
筋材的变形模量和布筋方向对加筋土强度有很大的影响,在这两方向进行的试验研究与理论分析,对加筋土结构的应用具有一定的参考价值。 相似文献
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碎石土加筋前后应力-应变关系的归一性左。围压越低,颗粒越硬,归一性越差;随围压增大,归一性增强。根据加筋前后各试验点的集中程度和围压大小,将碎石土的归一化直线划分为两条,并由归一化参数预测碎石土加筋前后的应力-应变关系。与实测曲线比较,不加筋时差别随围压增大和颗粒粗硬而增大;加筋时差别较小。同时根据归一性提出了描述该类土体切线剪切模量的归一化本构方程,其方程参数直接由三轴试验成果确定,并给出了所有 相似文献
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Cost Optimization of Reinforced Earth Walls 总被引:1,自引:0,他引:1
P. K. Basudhar Amol Vashistha Kousik Deb Arindam Dey 《Geotechnical and Geological Engineering》2008,26(1):1-12
This paper deals with optimum cost (objective function) design of geosynthetic reinforced earth retaining walls subjected
to static and dynamic loading. The design restrictions are imposed as design constraints in the analysis. Choice of the initial
designed length and strength of the reinforcement, which are the elements of the design vectors are made in a way that it
forms an initial feasible design vector. Thus the problem is one of mathematical programming. The constraints and the objective
function being nonlinear in nature, the Sequential Unconstrained Minimization Technique (SUMT) has been used in conjunction
with conjugate direction and quadratic fit methods for multidimensional and unidirectional minimization to arrive at the optimal
(minimum) cost of the reinforced earth wall. Optimal cost tables are presented for different combinations of the loading and
the developed procedure is validated by taking up an example problem. It has been found from the typical example problem that
saving of the order of 7–8% can be made over the conventional design of mechanically stabilized earth (MSE) walls with the
aid of design charts. 相似文献
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Priti Maheshwari P. K. Basudhar S. Chandra 《Geotechnical and Geological Engineering》2006,24(2):313-324
The paper describes a mechanical model for estimating the flexural response of a strip footing, supporting a column (imposing
a concentrated load), resting on a compacted granular bed overlying a reinforcement layer for example, geogrids, geomats etc.
below which lies a loose soil deposit. The footing is idealized as a beam and the reinforcing element is assumed to have finite
bending stiffness and negligible frictional resistance. The upper and lower soil layers are idealized by a series of linear
and discrete springs (Winkler springs) of different stiffness values. To find the response of such a model the governing differential
equations have been derived and expressed in a nondimensional form. A closed form analytical solution of the same has been
obtained subjected to appropriate boundary conditions. Using the present approach the resulting solution for a degenerated
case of a long beam is found to be identical to the same of Hetenyi (1946, Beams on elastic foundations, University of Michigan
press, Ann Arbor, MI). Parametric studies reveal that the ratio of flexural rigidity of upper and lower beam and the ratio
of stiffness of the upper and lower soil layers affect significantly the response of the foundation. 相似文献
6.
Effectiveness of glass fiber grids as a reinforcement of the asphalt layer in a flexible pavement system was investigated. The study involved both laboratory experimental work and computer analysis of pavement sections. Twenty flexible pavement sections (with and without glass fiber grids) were constructed and tested in the laboratory as a part of the experimental study. The laboratory-scale pavement sections were instrumented with pressure cells, displacement gages, and strain gages. Test sections were subjected to 1,000,000 load applications at a frequency of 1.2 Hz. Static loading tests were conducted at intervals of 100,000 load applications. In thirteen experiments, glass fiber grids were used as reinforcement in the asphalt layer. Several computer analyses of flexible pavement sections were performed by using the finite element method (FEM). The laboratory data were compared with results obtained from the computer analyses. Results from this study show that glass fiber grids can be used to improve the performance of flexible pavement systems. It was also observed that the inclusion of glass fiber grid in the asphalt layer provided resistance to crack propagation. Overall, the flexible pavement sections reinforced with glass fiber grids showed better performance under laboratory test conditions. 相似文献
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改性粘土增强硅橡胶性能的研究 总被引:1,自引:0,他引:1
改性粘土增强硅橡胶性能的研究魏从容吴季怀沈振(华侨大学材料物理化学研究所,泉州362011)关键词粘土矿物质表面改性硅橡胶增强剂粘土矿物作硅橡胶增强剂是粘土综合开发利用的新课题,我们在这方面取得一定的成果[1]。但是,未经改性处理的粘土其增强能力是有... 相似文献
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Lazhar Belabed Hacene Benyaghla Jarir Yahiaoui 《Geotechnical and Geological Engineering》2011,29(4):443-452
The stabilization of slopes by the technique of reinforced earth (Terre Armée) is a very economical and reliable technique.
We propose in this paper to check the overall internal stability of the reinforced earth retaining walls by three mechanical
models, using the analytical method of the limit equilibrium (failure). The main objective of this paper is to compare these
failure mechanical models with the failure models obtained by numerical analysis (code FLAC 2D), in order to validate the
most realistic and more unfavourable failure models. Parametric and comparative studies carried out have allowed us to bring
a very useful knowledge concerning the study of the internal stability of the reinforced earth retaining walls. It also proposed
a theoretical mechanical model of calculation proved by numerical simulation. 相似文献
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Cellular reinforcement is a three dimensional reinforcement used for reinforced soil structures. Behaviour of such reinforcement
is important for its use in actual practice. Present paper focuses on the behavior of cellular reinforcement in sand under
the triaxial loading conditions. Series of triaxial tests are performed on unreinforced and reinforced sand with single layer
as well as double layers of cellular reinforcements with 75 mm sample diameter. Six different reinforcement heights of cellular
reinforcements (varying from 3 to 50 mm) are used along with one sheet reinforcement of thickness 1 mm. From the experimental
failure patterns of the triaxial samples, multiple zones of failure are observed as an effect of cellular reinforcement. Deviator
stress–strain curves are studied for single and double layers of cellular reinforcement under three different confining pressures.
Peak deviator stress is found increasing with increasing height of cellular reinforcement, which shows the confining effect
of cellular reinforcement. Shear strength parameters are evaluated and are found increasing with increase in height of cellular
reinforcement, also cellular reinforcement with heights 10 mm and more have showed increased shear strength parameters, as
compared to 1 mm thick sheet reinforcement. This assures better behavior performance of cellular reinforcement over the planar
one. Failure patterns are also visualized by finite element analysis and found in accord with experimental observations Horizontal
displacement for reinforced samples visualized multi-zoned failure pattern. Finite element results for deviator stress–strain
relationship are found in reasonably good accord with experimental results. 相似文献
16.
Salah Messioud Umur Salih Okyay Badreddine Sbartai Daniel Dias 《Geotechnical and Geological Engineering》2016,34(3):789-805
The rigid-pile soil-improvement technique aims to increase the bearing capacity of the soil and decrease the settlement of the surface structure. The most remarkable difference of this technique from the deep-foundation system is the soil layer between the pile heads and the structure. This soil layer, called the mattress, is made of compacted granular materials and participates in the load transfer through arching and shear mechanisms. In order to understand the dynamic behavior of rigid-pile reinforced soils, tri-dimensional finite-element analyses of a soil-pile-slab system, a soil-pile-mattress-slab system, and a soil-pile-mattress-embankment system are presented in this paper. Different geometric configurations are studied in terms of dynamic impedances. The soil, piles, mattress, and embankment are represented as continuum solids, and the slab is represented by structural plate-type elements. The horizontal and vertical impedances of pile foundations are presented and the results are compared with studies in the literature. This study shows the influence of the mattress stiffness, the geometrical configuration, and head/tip fixity conditions on the dynamic response of the foundation system. A comparison between rigid piles and pile foundations is then presented. 相似文献
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Sludge is a kind of solid waste with high natural moisture content and extremely poor mechanical properties. Adopting effective technical methods for rapid dewatering and increasing strength is an important prerequisite for realizing the utilization and efficient utilization of sludge resources. In this paper, discrete short-staple polypropylene fiber was selected as the reinforced material, cement and fly ash were used as the solidified materials. The unconfined compression test was carried out to study the strength change of the fiber reinforced solidified sludge in the drying path, and the drying was analyzed. The influence mechanism of different target moisture content states(5 ~45 ) and fiber content(0~0.8 ) on the strength of reinforced solidified sludge during the process. The results show that: The addition of fiber can effectively improve the peak strength and residual strength of solidified sludge, and the strength value increases first and then decreases with the increase of fiber content, and the optimal fiber content is 0.1 . During the drying process, the sample of the unconfined compressive strength increases with the decrease of the moisture content of approximate to linear, and the damage form by the plastic damage to brittle fracture transition gradually, and the addition of fibers can effectively restrain the brittle failure sample, enhance the toughness of specimen. The contribution of fiber reinforcement to the strength of solidified sludge increases gradually with the decrease of moisture content, and the root cause is that the fiber-sludge interface force can be better excited under the condition of low moisture content. 相似文献
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淤泥是一种天然含水率高且力学性质极差的固体废弃物,采取有效的技术方法进行快速脱水和增强可以实现淤泥资源化和高效利用。选取离散短丝聚丙烯纤维作为加筋材料,水泥和粉煤灰作为固化材料,通过开展无侧限抗压试验,研究了纤维加筋固化淤泥在干燥路径中强度的变化,并分析了干燥过程中不同目标含水率状态(分别为45%,40%,35%,30%,25%,20%,15%,10%和5%)和纤维掺量(0~0.8%)对加筋固化淤泥强度的影响机理。结果表明:①纤维的加入能有效提高固化淤泥的峰值强度和残余强度,且强度值随纤维掺量的增加呈现先上升后下降的趋势,最优纤维掺量为0.1%;②干燥脱水过程中,试样的无侧限抗压强度随含水率的减小近似于线性增加,破坏形式由塑性破坏逐渐向脆性破坏过渡,而纤维的加入可以有效抑制试样的脆性破坏,提升试样的韧性;③纤维加筋对固化淤泥强度的贡献随含水率的减小而逐渐增加,根本原因是纤维—淤泥界面作用力在低含水率条件下能得到更佳的激发。 相似文献
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土工加筋抗冻胀工作机制的研究 总被引:2,自引:0,他引:2
在分凝势理论的基础上,建立了一套考虑温度、水分及冻土-未冻土-筋材体系应力变形诸因素耦合预测加筋土冻胀和筋材拉力的计算方法,并对一维冻结室内模拟试验进行了理论分析和数值计算。通过对加筋消减冻胀及其抗冻胀工作机制的分析,提出了加筋材料对土体施加的约束,不仅减小了土体的冻胀速率,而且还使冻胀位移向未冻土区发展,从而可有效地消减土体冻胀的结论。 相似文献