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1.
Small-Strain Shear Modulus and Damping Ratio of Sand-Rubber and Gravel-Rubber Mixtures 总被引：2，自引：0，他引：2
Anastasios Anastasiadis Kostas Senetakis Kyriazis Pitilakis 《Geotechnical and Geological Engineering》2012,30(2):363-382
This study examines the small-strain dynamic properties of mixtures composed of sandy and gravelly soils with granulated tire
rubber in terms of shear modulus (GO), and damping ratio in shear (Dmin). Torsional resonant column tests are performed on dry, dense specimens of soil-rubber mixtures in a range of soil to rubber
particles size 5:1–1:10 and rubber content from 0 to 35% by mixture weight. The experimental results indicate that the response
of the mixtures is significantly affected by the content of rubber and the relative size of rubber to soil particles. Concering
the small-strain shear modulus, an equivalent void ratio is introduced that considers the volume of rubber particles as part
of the total volume of voids. Based on a comprehensive set of test results a series of equations were developed that can be
used to evaluate the shear modulus and damping ratio at small shear strain levels if the confining pressure, the content of
rubber by mixture weight, the grain size of soil and rubber particles, and the dynamic and physical properties of the intact
soil are known. 相似文献
2.
天然土尤其是地表浅层土常处于非饱和状态,其小应变剪切模量是预测地基变形及土工结构物动力反应的一个重要参数。通过对非饱和压实粉土三轴样进行弯曲元试验,研究了吸力和干湿路径对其小应变剪切模量的影响。试验结果表明,非饱和压实粉土样的小应变剪切模量各向异性忽略不计;小应变剪切模量G0(vh)、G0(hh)和G0(hv)均随吸力增大而非线性增大;同一吸力下不同干湿路径上的土样,饱和度不同,其小应变剪切模量随饱和度升高而减小,主要原因是土的平均骨架应力和土中毛细水的作用。根据试验结果对非饱和土小应变剪切模量的半经验公式进行了改进,同时考虑了吸力与饱和度的作用。 相似文献
3.
非饱和土的抗剪强度与含水率关系的试验研究 总被引：10，自引：0，他引：10
研究非饱和土的抗剪强度及其随含水率的变化规律,对工程实践具有重要意义。在总结前人试验研究成果的基础上,以欠固结的第三系粉砂土为研究对象,对原状土和两种控制含水率方法的重塑土进行直剪试验,并与前人研究进行对比。研究结果表明,随着含水率的增加,土的抗剪强度降低,含水率对抗剪强度的影响主要是降低了土的黏聚力,对内摩擦角的影响较小。含水率与黏聚力之间的关系可以由两个直线段描述,第2直线段的斜率要大于第1直线段,当含水率增加到一定值时,土的黏聚力急剧下降。通过控制干密度,添加不同质量的水来改变土样含水率的重塑土方法,不仅改变了土样的含水率,还改变了土的压实度和颗粒结构,因此,土的抗剪强度的变化是含水率和压实度共同影响的结果,在分析试验结果时应该引起重视。 相似文献
4.
Mousa F. Attom 《Environmental Geology》2008,55(4):781-788
Iron filling and iron filling–cement mixture were used to improve the shear strength characteristics of Irbid clayey soil.
For this purpose, five types of Irbid clay soils were obtained and mixed with iron filling and iron filling–cement mixture
at different percentages. Two sets of prepared samples were mixed with the admixture. The first set was prepared by mixing
the soil samples with iron filling alone at 2.5, 5.0, 7.5, and 10% by dry weight of the soil. The second set was prepared
by mixing with iron filling–cement mixture at equal ratio of the same percentages of the first set. An unconfined compression
test was performed in this study to measure the shear strength properties of the soils. The test results showed that the increase
in the percentages of the iron filling and iron filling–cement mixture up to 10% will result in increasing the maximum dry
density of the soil and increase the unconfined compressive strength and the secant of modulus of elasticity of the clayey
soil. Also, the addition of iron filling–cement mixture increased the unconfined compressive strength and secant modulus of
elasticity of the clayey soil higher than the addition of iron filling alone. 相似文献
5.
Maher Omar Abdallah Shanableh Adnan Basma Samer Barakat 《Geotechnical and Geological Engineering》2003,21(3):283-295
Most of the topsoils encountered in United Arab Emirates and in the Arabian Peninsula are granular soils with small percentages
of silt and clay. Determination of the compaction characteristics of such soils is an essential task in preparing for construction
work. The accumulating experience over many years of soil testing in our laboratories suggested that there exists an underlying
trend that governs the compaction characteristics of such soils. As such, a study was undertaken to assess the compaction
characteristics of such soils and to develop the governing predictive equations. For the purposes of this study, 311 soil
samples were collected from various locations in the United Arab Emirates, and tested for various including grain-size distribution,
liquid limit, plasticity index, specific gravity of soil solids, maximum dry density of compaction, and optimum moisture content
following ASTM D 1557-91 standard procedure C. Following the development of the predictive equations, a new set of 43 soil
samples were collected and their compaction results were used to test the validity of predictive model. The range of variables
for these soils were as follows: percent retained on US sieve #4 (R#4): 0–68; Percent passing US sieve #200 (P#200): 1–26;
Liquid limit: 0–56; Plasticity index: 0–28; Specific gravity of soil solids: 2.55–2.8.
Based on the compaction tests results, multiple regression analyses were conducted to develop mathematical models and nomographic
solutions to predict the compaction properties of soils. The results indicated that the nomographs could predict well the
maximum dry density within ±5% confidence interval and the optimum moisture content within ±3%.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
In order to recycle the incineration fine bottom ash generated from municipal solid waste as a fine aggregate construction
material(<4.75 mm), a series of uniaxial compression tests were carried out according to the mixing ratio of bottom ash, the
curing temperature, the water–cement ratio, the mixing ratio of expanded poly styrene (EPS), and the curing time. As the results
of tests, the compression strengths cured 28 days of all specimens prepared with different mixing ratios are ranged between
87 and 220 kg/cm2. The water content of the hardened cement mortar is not much different with the curing time. Also, the water content is increased
with increasing the mixing ratio of bottom ash, the water–cement ratio, and the mixing ratio of EPS. The unit weight of the
hardened cement mortar is decreased with increasing the mixing ratio of bottom ash and the mixing ratio of EPS. The compression
strength of the hardened cement mortar is decreased with increasing the mixing ratio of bottom ash. The compression strength
of the hardened cement mortar cured at 30 ± 2°C and 40 ± 2°C is bigger than that of the cement mortar cured at normal temperature
(20 ± 2°C). However, the compression strength of the hardened cement mortar cured at 30 ± 2°C is bigger than that of the cement
mortar cured at 40 ± 2°C. The compression strength is increased at the range from 0.55 to 0.6 of water–cement ratio, and then
the compression strength is decreased over 0.65 of water–cement ratio. Meanwhile, the compression strength of the hardened
cement mortar is decreased with increasing the mixing ratio of EPS. 相似文献
7.
Groundnut shell ash, cement and their combinations are used as soil stabilizers in various percentages to improve the strength of locally available highly compressible clay soil. The effect of stabilizer in improving the strength of the soil is evaluated through change in consistency limits, compaction characteristics, undrained cohesion and modulus of elasticity. The durability characteristics of stabilised soil were studied based on the improvement of undrained shear strength for various days of curing by increasing the percentage of cement. Stabilised soil showed satisfactory improvement in strength and consistent durability characters. Groundnut shell ash and cement increased the optimum moisture content. There was a slight decrease in the dry density and modulus of elasticity of soil. These can be used as a viable economic alternative in construction of roads and for stabilising soil acting as bearing medium. The use of groundnut shell ash, an agricultural waste, helps in waste management and promotes sustainable development of local construction industry. 相似文献
8.
用似水灰比对水泥土无侧限抗压强度的预测 总被引：12，自引：1，他引：11
对以连云港地区的海相软土为原料的水泥土进行了一系列物理、强度试验,分析了含水量、水泥用量和龄期对水泥土强度的影响,提出了似水灰比的概念用于水泥土强度的预测。采用提出的水泥土强度预测公式,根据某一似水灰比、龄期28 d某种的水泥土室内试验强度,可以预测不同含水量、不同水泥用量和不同龄期的水泥土室内试验强度。通过比较分析发现,得出水泥土强度预测公式可以很好地应用于其他研究者已经发表的水泥土试验数据,进一步验证了所提出的强度预测公式的有效性。 相似文献
9.
Recently in China, soil–cement is widely used to improve the soft ground in the highway construction engineering. Literature
studies are mainly investigating the mechanical properties of the soil–cement, while its properties of the electrical resistivity
are not well addressed. In this paper, the properties of the electrical resistivity of the reconstituted soil-cement and the
in situ soil–cement columns are investigated. The test results show that the electrical resistivity of the soil–cement increases
with the increase in the cement-mixing ratio and curing time, whereas it decreases with the increase in the water content,
degree of saturation and water–cement ratio. A simple equation is proposed to predict the electrical resistivity of soil–cement
under the condition of the specified curing time and water–cement ratio. It is found that the electrical resistivity has a
good relationship with the unconfined compression strength and blow count of SPT. It is expected that the electrical resistivity
method can be widely used for checking/controlling the quality of soil–cement in practice. 相似文献
10.
Yahia E.-A. Mohamedzein Amer A. Al-Rawas 《Geotechnical and Geological Engineering》2011,29(6):999-1008
Sabkha soils are salt-bearing formations that are formed in arid regions. In their in situ states the sabkha soils have high
compressibility and low shear strength. These soils are also heterogeneous and their properties depend on the type and amount
of salt present. Thus, these soils are not suitable for support of infrastructures without the risk of high settlement and/or
bearing capacity failure. This paper investigates the possibility of using cement to improve the shear strength of sabkha
soils for possible use as a foundation-bearing soil. The sabkha soil used in this study is a sandy sabkha obtained from the
coastal plains at Al-Auzayba, Sultanate of Oman. Cement was added in percentages of 2.5, 5, 7.5 and 10%, by dry weight of
soil. The soil-stabilizer mixers were allowed to cure for 7, 14 and 28 days. Laboratory tests such as compaction, unconfined
compression, consolidated undrained triaxial and durability tests were performed to measure the engineering characteristics
of the stabilized material. The results showed substantial improvements in the shear strength of the sabkha–cement mixtures
and the mixtures are also durable with small weight loss after 12 wetting/drying cycles. Thus, cement can be used to improve
the shear strength of sabkha soils. Furthermore, the effective stress path and the tress-strain relation of the sabkha–cement
mixtures follow trends similar to those of cemented calcareous soils. 相似文献
11.
冻融作用下PPF稳定土力学性能研究 总被引：4，自引：4，他引：0
为了研究冻融作用下外加材料稳定土的力学性能,以一种国产土壤固化剂（TG固化剂）加固低剂量水泥石灰稳定土为研究对象,通过冻融前后的无侧限抗压强度试验、劈裂强度试验和抗压回弹模量试验,研究不同压实度、聚丙烯纤维（PPF）掺量稳定土的力学性能。结果表明：稳定土的抗压强度、劈裂强度及回弹模量均随冻融次数的增加而降低,经历6次冻融循环后,强度、模量损失率基本稳定。冻融前后稳定土的抗压强度、劈裂强度、抗压回弹模量以及强度、模量的残留百分比均随着压实度和PPF掺量的提高而增大。结合工程实际情况,选取压实度为95%,0.2% PPF综合稳定土进行冻融试验,得到抗压强度残留比（BDR）达到59.32%,质量变化率仅为6.28%,研究表明,PPF综合稳定土具有优良的冻稳定性,可用作路面基层材料。 相似文献
12.
Evangelos I. Stavridakis 《Geotechnical and Geological Engineering》2006,24(2):379-398
Major geotechnical problems in construction involving silty–clayey soils are due to their low strength, durability and high
compressibility of soft soils, and the swell–shrink nature of the overconsolidated swelling soils. Confronted with these problems,
a suitable ground improvement technique is needed, for deep excavations in soft clays, for stability, durability and deformation
control. Cement-stabilization is one of the alternatives. An increase in strength and durability, reduction in deformability
are the main aims of this method. Conventional cement-stabilization methods are used mainly for surface treatment. However,
the use of cement has recently been extended to a greater depth in which cement columns were installed to act as a type of
soil reinforcement (deep cement–soil mixing and cement jet grouting). In situ engineering properties of these silty–clayey soils are often variable and difficult to predict. For this reason cement-stabilization
methods have a basic target to control the aforementioned engineering properties of these clays so that the properties of
a silty–clayey soil become more like the properties of a soft rock such as clayey shale or lightly cemented sandstone. So
cement-stabilization of these soils is essential to control their engineering properties and to predict their engineering
behaviour for construction. In an effort to predict, classify and study the suitability of silty–clayey soils for cement-stabilization
both slaking and unconfined compressive strength tests were carried out on clayey–sand mixtures consisted of two types of
clays, kaolin and bentonite. Finally diagrams were prepared to study the variation of slaking and strength due to compaction,
curing time and cement percentage and also to predict areas of efficient cement-stabilization. 相似文献
13.
Geotechnical properties of municipal sewage sludge 总被引：3，自引：0，他引：3
Brendan C. O’Kelly 《Geotechnical and Geological Engineering》2006,24(4):833-850
The geotechnical properties of municipal sewage sludge, in particular those pertinent to the handling and landfilling of the
material, are presented. Index, drying, compaction, shear strength and consolidation tests were conducted on the material
at different states of biodegradation. The organic content and specific gravity of solids were found to be inversely related,
with typical organic contents of 50–70% and specific gravity of solids values of 1.55–1.80. The density of the compacted material
was low in comparison with mineral soils. Standard Proctor compaction yielded a maximum dry density of 0.56 tonne/m3 at 85% water content. Laboratory vane-shear and triaxial compression tests indicated that, below about 180% water content,
the shear strength of the sludge material increased exponentially with reducing water content. Consolidated-undrained triaxial
compression tests on the pasteurised sludge material indicated an effective angle of shearing resistance of 32° for the moderately
degraded material and 37° for the strongly degraded material. Biogas was produced at rates of up to 0.33 L/day/kg slurry due
to ongoing biodegradation and the resulting pore pressure response must be taken into account in any stress analysis. Consolidation
tests using the hydraulic consolidation cell, oedometer and triaxial apparatus indicated that the sludge material was highly
compressible although practically impermeable, for example the coefficient of permeability for the moderately degraded slurry
was of the order of 10−9m/s. However, creep deformation was significant with typical coefficient of secondary compression values of 0.02–0.08 for
the compacted material. A more free-draining material was produced at higher states of biodegradation. 相似文献
14.
Junboum Park Cumaraswamy Vipulanandan Jee Woong Kim Myoung Hak Oh 《Environmental Geology》2006,49(7):977-989
Biosurfactants are frequently used in petroleum hydrocarbon and dense non-aqueous phase liquids (DNAPLs) remediation. The
applicability of biosurfactant use in clayey soils requires an understanding and characterization of their interaction. Comprehensive
effects of surfactants and electrolyte solutions on kaolinite clay soil were investigated for index properties, compaction,
strength characteristics, hydraulic conductivities, and adsorption characteristics. Sodium dodecyl sulfate (SDS) and NaPO3 decreased the liquid limit and plasticity index of the test soil. Maximum dry unit weights were increased and optimum moisture
contents were decreased as SDS and biosurfactant were added for the compaction tests for mixtures of 30% kaolinite and 70%
sand. The addition of non-ionic surfactant, biosurfactant, and CaCl2 increased the initial elastic modulus and undrained shear strength of the kaolinite–sand mixture soils. Hydraulic conductivities
were measured by fixed-wall double-ring permeameters. Results showed that the hydraulic conductivity was not significantly
affected, but slightly decreased from 1×10−7 cm/s (water) to 0.3×10−7 cm/s for Triton X-100 and SDS. The adsorption characteristics of the chemicals onto kaolinite were also investigated by developing
isotherm curves. SDS adsorbed onto soil particles with the strongest bonding strength of the fluids tested. Correlations among
parameters were developed for surfactants, electrolyte solutions, and clayey soils. 相似文献
15.
Analysis of Swelling and Shrinkage Behavior of Compacted Clays 总被引：2，自引：0，他引：2
Anil Kumar Mishra Sarita Dhawan Sudhakar M. Rao 《Geotechnical and Geological Engineering》2008,26(3):289-298
The impact of the variation in compaction condition on the swelling and shrinkage behavior of three soils has been examined.
Two natural soils, namely red soil and black cotton soil, and one artificially mixed soil sample of commercial bentonite with
well-graded sand, were studied. Compaction curve for Standard Proctor conditions were plotted and four compaction conditions
were selected. Experimental results showed that clay mineralogy dominates over compaction conditions in influencing the swelling
and shrinkage behavior of the tested soils. Monitoring of void ratio (e)−water content (w) relations during shrinkage showed
that soil specimens generally shrunk in three distinct linear stages. A small reduction in void ratio occurred on reduction
in water content during the first shrinkage stage and was termed as initial shrinkage. In second stage, void ratio decreased
rapidly with reduction in water content and was termed as primary shrinkage. In third and final stage, reduction in water
content is accompanied by a marginal change in void ratio and it’s called residual shrinkage. Irrespective of initial compaction
conditions studied, the transition from primary to residual shrinkage for all the specimens occurred within a narrow range
of water content (10–15%). 相似文献
16.
水泥改良高液限黏土动态回弹模量试验研究 总被引：3，自引：0，他引：3
利用动三轴试验,研究了水泥改良高液限黏土动态回弹模量的影响因素及其变化规律。研究表明,动态回弹模量随围压、压实度和水泥含量的提高而增大,随循环偏应力和含水率的增大而减小。为分析动态回弹模量的应力依赖性,研究采用了双因素方差分析。分析表明,偏应力与围压均对动态回弹模量有显著性影响,但偏应力的影响更为显著。鉴于动态回弹模量是偏应力和体应力的函数,在分析现有动态回弹模量本构模型适应性的基础上,采用偏应力和体应力为变量的3参数复合模型对试验数据进行回归分析,结果表明,所选模型具有较高的决定系数,证明所选模型具有较高的合理性与可靠性。研究获得了不同含水率、压实度和水泥剂量下水泥改良高液限黏土的动态回弹模量预估模型,为基于动力学的路面结构设计提供了参数。 相似文献
17.
S. M. Haeri A. Hamidi S. M. Hosseini E. Asghari D. G. Toll 《Geotechnical and Geological Engineering》2006,24(2):335-360
The behavior of a cemented gravely sand was studied using triaxial compression tests. Gypsum, Portland cement and lime were
used as the cementing agents in sample preparation. The samples with different cement types were compared in equal cement
contents. Three cement contents of 1.5%, 3.0% and 4.5% were selected for sample preparation. Drained and undrained triaxial
compression tests were conducted in a range of confining pressures from 25 kPa to 500 kPa. Failure modes, shear strength,
stress–strain behavior, volume and pore pressure changes were considered. The gypsum cement induced the highest brittleness
in soil among three cement types while the Portland cement was found to be the most ductile cementing agent. In lower cement
contents and lower confining pressures the soil cemented with Portland cement showed the highest shear strength. However,
in the same range of cement content, the soil cemented with gypsum showed highest shear strength for highest tested confining
stress. For higher cement contents the shear strength of soil cemented with Portland cement is higher than that for the two
other cement types for the range of confining pressures tested in the present study. The samples cemented with lime had the
least peak and ultimate shear strength and the highest pore pressure generation in undrained tests. Contrary to the soil cemented
with lime, the brittleness of soil cemented with gypsum and Portland cement reduces in undrained condition. Finally it was
found that the effect of cement type on the shear strength of cemented soils is more profound in drained condition compared
to undrained state. 相似文献
18.
Omar Saeed Baghabra Al-Amoudi 《Engineering Geology》1994,36(3-4):279-291
Vast expanses of arid, saline soils that occur along the Arabian Gulf seaboard and elsewhere possess a very low density and strength that necessitate improvement before any actual construction takesplace. For large-scale constructions, several field improvement techniques have recently been implemented with various degrees of success. In surficial, small-scale applications, chemical stabilization provides a potential technique to improve the inferior properties of these soils, known locally as sabkha. A literature search indicates that chemical stabilization of soils usingasphalt, lime and cement is usually conducted at lower moisture contents than the optimum. Such moisture contents are also much lower than the natural moisture content of sabkha, and if applied to sabkha in the field, this wouldrequire lowering the moisture content before any stabilization commenced; whichwould be neither feasible nor economical.
In this investigation, an eastern Saudi sabkha soil was chemically stabilized at its natural moisture level, which varies from 16% to 22%. In addition to the characterization of the soil and standard compaction tests, cement and lime sabkha mixtures were prepared at five additions and cured for up to 90 days in plastic wrap. Results indicate that cement-stabilized sabkha gained high strength with time and proved to have a potential use in construction. 相似文献
19.
20.
绢云母片岩粗粒料改性试验研究 总被引：2，自引：0，他引：2
绢云母片岩属极软岩,强度低,直接作为路基填料难以压实,易造成路基沉陷、路面开裂等不良工程现象。通过对绢云母片岩及其4种改性方案进行表面振动压实试验、室内重型击实试验、室内CBR试验以及回弹模量试验研究,探讨绢云母片岩经改性后用作高速公路路基填料的适用性。试验表明,绢云母片岩最大干密度采用室内重型击实与表面振动压实试验结果相差较大,采用表面振动压实时为1.92 g/cm3,采用室内重型击实时为2.01 g/cm3。主要原因是由于绢云母片岩颗粒破碎的结果。绢云母片岩及其4种改性粗粒土的在最优含水率附近的较宽范围内的变动对压实效果的影响不大,有利于填料的压实。绢云母片岩的回弹模量E较低,小于32 MPa,经改性后的土料的回弹模量均有显著提高,均达到50 MPa以上。添加20%红砂岩和20%黏性土的试料CBR值均只有3.7,添加3%水泥和5%水泥的试料CBR值上升明显。绢云母片岩经添加3%、5%的水泥化学改性后可用于高速公路上路堤及路床填筑。 相似文献