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Rapid testing and prediction of soil–water characteristic curve of subgrade soils considering stress state and degree of compaction 被引量:2
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作者 Junhui Peng Huiren Hu Junhui Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第12期3305-3315,共11页
The subgrade soil is generally in saturated or unsaturated condition. To analyze complex thermo-hydro-mechanical-chemical (THMC) behaviors of subgrade, it is essential to determine the soil–water characteristic curve... The subgrade soil is generally in saturated or unsaturated condition. To analyze complex thermo-hydro-mechanical-chemical (THMC) behaviors of subgrade, it is essential to determine the soil–water characteristic curve (SWCC) that represents the relationship between matric suction and moisture content. In this study, a full-automatic rapid stress-dependent SWCC pressure-plate extractor was developed. Then, the influences of overburden stress and degree of compaction on the SWCC of subgrade soil such as high liquid limit silt (MH) and low liquid limit clay (CL) were analyzed. Accordingly, a new model taking into account the influences of overburden stress and degree of compaction based on the well-known Van Genuchten (VG) SWCC fitting model was presented and validated. The results show that with the increase of the degree of compaction and overburden stress, the saturated moisture content of subgrade soil decreases, while the air-entry value increases and the transition section curve becomes flat. The influences of the degree of compaction and overburden stress on the SWCC of MH is greater than that of CL. Meanwhile, there was a satisfactory agreement between the prediction and measurement, indicating a good performance of the new model for predicting the SWCC. 展开更多
关键词 Subgrade soil Soil–water characteristic curve(SWCC) Overburden stress degree of compaction Prediction mode
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Degree of Compactness in I-fuzzy Topological Spaces 被引量:1
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作者 李宏艳 《Northeastern Mathematical Journal》 CSCD 2008年第6期485-491,共7页
In this paper, the concept of degree of compactness is introduced in the general framework of I-fuzzy topological spaces, and its property is discussed. All good compactness are generalized to I-fuzzy topological spac... In this paper, the concept of degree of compactness is introduced in the general framework of I-fuzzy topological spaces, and its property is discussed. All good compactness are generalized to I-fuzzy topological spaces accordingly. 展开更多
关键词 I-fuzzy topology value set of compactness degrees of compactness
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Influence of Compaction Pressure on the Accelerated Carbonation of Calcium Hydroxide 被引量:1
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作者 房延凤 常钧 CAO Mingli 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第6期1187-1192,共6页
Mineral carbonation using waste cement is a promising method to solve the problems caused by CO_2 emission and waste cement. Compaction pressure is an important parameter for mineral carbonation of calcium hydroxide, ... Mineral carbonation using waste cement is a promising method to solve the problems caused by CO_2 emission and waste cement. Compaction pressure is an important parameter for mineral carbonation of calcium hydroxide, one of the most dominant composite of waste cement that can be carbonated. The carbonation degree, morphology of products and compressive strength of carbonated compacts are influenced by compaction pressure significantly. Results show that the carbonation degree of calcium hydroxide increases at first(0-8 MPa) and then decreases in the higher compaction pressure range(10-14 MPa). At the meantime, results also indicate that lower compaction pressure accelerates the early carbonation but hinder carbonation in the later stages. For the morphologies of carbonation products, calcium carbonate tends to form typical crystal morphology of calcite(rhombohedral) under lower compaction pressure, while it will become ellipsoidlike when compaction pressure reaches 8 MPa. TGA and water content results show that there is an optimal water content for the carbonation. In addition, lower water content is adverse to the carbonation at later stage and the CO_2 is difficult to penetrate into the inside of compacts when water content is high, which will hinder the carbonation. XRD and TGA results show that the carbonation products are calcite and small amount of amorphous calcium carbonate. 展开更多
关键词 calcium hydroxide accelerated carbonation mass gain degree compaction pressure
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COMPACTNESS DEGREE AND A GENERALIZATION OF THE TYCHONOFF THEOREM
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作者 李邦河 冯汉桥 《Acta Mathematica Scientia》 SCIE CSCD 1990年第4期422-426,共5页
The most interesting result of this paper is the following generalization of the Tychonoff theorem: [GRAPHICS].
关键词 TH over COMPACTNESS degree AND A GENERALIZATION OF THE TYCHONOFF THEOREM
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Influence of soil density on gas permeability and water retention in soils amended with in-house produced biochar 被引量:2
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作者 Ankit Garg He Huang +6 位作者 Weiling Cai Narala Gangadhara Reddy Peinan Chen Yifan Han Viroon Kamchoom Shubham Gaurav Hong-Hu Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2021年第3期593-602,共10页
Biochar has been used as an environment-friendly enhancer to improve the hydraulic properties(e.g.suction and water retention)of soil.However,variations in densities alter the properties of the soil ebiochar mix.Such ... Biochar has been used as an environment-friendly enhancer to improve the hydraulic properties(e.g.suction and water retention)of soil.However,variations in densities alter the properties of the soil ebiochar mix.Such density variations are observed in agriculture(loosely compacted)and engineering(densely compacted)applications.The influence of biochar amendment on gas permeability of soil has been barely investigated,especially for soil with different densities.The major objective of this study is to investigate the water retention capacity,and gas permeability of biochar-amended soil(BAS)with different biochar contents under varying degree of compaction(DOC)conditions.In-house produced novel biochar was mixed with the soil at different amendment rates(i.e.biochar contents of 0%,5%and 10%).All BAS samples were compacted at three DOCs(65%,80%and 95%)in polyvinyl chloride(PVC)tubes.Each soil column was subjected to dryingewetting cycles,during which soil suction,water content,and gas permeability were measured.A simplified theoretical framework for estimating the void ratio of BAS was proposed.The experimental results reveal that the addition of biochar significantly decreased gas permeability kg as compared with that of bare soil(BS).However,the addition of 5%biochar is found to be optimum in decreasing kg with an increase of DOC(i.e.k_(g,65%)>k_(g,80%)>k_(g,95%))at a relatively low suction range(<200 kPa)because both biochar and compaction treatment reduce the connected pores. 展开更多
关键词 BIOCHAR degree of compaction(DOC) Gas permeability Soil water retention Wettingedrying cycle
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Study on mechanical properties of soil-rock mixture of various compactness subjected to freeze-thaw cycles 被引量:2
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作者 Zhong Zhou HaoHui Ding +1 位作者 WenYuan Gao LinRong Xu 《Research in Cold and Arid Regions》 CSCD 2021年第5期450-462,共13页
The soil-rock mixture,a collection of soil particles and rock blocks,is inherently heterogeneous and anisotropic due to significant particle size and material strength differences.This study conducts triaxial tests on... The soil-rock mixture,a collection of soil particles and rock blocks,is inherently heterogeneous and anisotropic due to significant particle size and material strength differences.This study conducts triaxial tests on soil-rock mixture samples of various compactness subjected to varying freeze-thaw cycles.A mesoscopic simulation is carried out by particle flow code(PFC)to analyze the effects of freeze-thaw cycles on the mechanical properties of soil and rock particles.The results show that the mechanical properties of the soil-rock mixture under freeze-thaw cycles are greatly affected by the initial compaction.In general,when the degree of compaction is higher,the influence of freeze-thaw cycles on the soil-rock mixture is greater.The stress-strain curves of the samples with different compactness demonstrate strain-softening behavior.The freeze-thaw cycles greatly influence the failure strength of the samples with a higher degree of compaction but have little impact on the samples with a lower degree of compaction.On the microscopic level,during freeze-thaw cycles,the pore volume in the highly compacted sample is too small to accommodate the volume expansion from ice crystal formation,causing significant strength loss among the soil and rock particles and deterioration of the macroscopic properties of the soil-rock mixture. 展开更多
关键词 soil-rock mixtures freeze-thaw cycle degree of compaction particle flow code
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Comprehensive tests on rising height of capillary water for coarse grained soil 被引量:4
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作者 GUO Qingsong LI Xin LI Min 《Global Geology》 2013年第1期54-58,共5页
According to the comprehensive tests on the rising height of capillary water for seven kinds of differ- ent coarse grained soil by use of the method of standpipe, the relationship between the rising height of capillar... According to the comprehensive tests on the rising height of capillary water for seven kinds of differ- ent coarse grained soil by use of the method of standpipe, the relationship between the rising height of capillary water and time was obtained, and the influencing factors and rules were analyzed. The data of the steady rising height of capillary water were obtained, and the regression equation of coarse grained soil on steady height and physical indexes (effective grain dl0 and porosity n) was found. Compared with Hazen's and other expressions that could estimate the steady height of capillary water of coarse grained soil, the proposed method is satisfactory and the defects of the latter were pointed out. 展开更多
关键词 method of standpipe coarse grained soil rising height of capillary water degree of compaction
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Some New Fixed Point Theorems in Probabilistic Metric Spaces 被引量:14
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作者 朱传喜 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1995年第2期179-185,共7页
In this paper, we introduce the concept of the Z-M-PN space and obtain somenew fixed point theorems in probabilistic metric spaces Meanwhile,some famous fixedpoint theorems are generalized in probabilistic metric spac... In this paper, we introduce the concept of the Z-M-PN space and obtain somenew fixed point theorems in probabilistic metric spaces Meanwhile,some famous fixedpoint theorems are generalized in probabilistic metric spaces, such a.s fixed point theorem of Schauder, Guo's theorem and fixed point theorem of Petryshyn are generalized in Menger PN-space. And fixed point theorem of Altman is also generalized in the Z-M-PN space. 展开更多
关键词 topological degree. probabilistic metric spaces. operator.compact continuous operator. Z-M-PN space
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Degree of compaction and compression strength of Nigerian Alfisol under tilled condition and different machinery traffic passes
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作者 Fasinmirin Johnson Toyin Adesigbin Adedayo Joseph 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2012年第2期34-41,共8页
Information on the effect of soil compaction on soil mechanical properties such as degree of compaction,compression and shear strength of tropical soils of Nigeria under different machinery traffic passes is very scar... Information on the effect of soil compaction on soil mechanical properties such as degree of compaction,compression and shear strength of tropical soils of Nigeria under different machinery traffic passes is very scarce.Field experiment was conducted in a tilled and compacted sandy clay loam(Alfisol)in Akure,Nigeria,under different machinery traffic passes to determine compaction effects on bulk density,compression strength,degree of compaction and the shear strength of soil.Four plots,A,B,C and D of area 20 m×50 m each were used for the field experiment.Treatment plot A was tilled with a tractor-mounted disc plough,and the remaining three plots:B,C and D were subjected to 5,10 and 15 to and fro passes,respectively,using heavy duty Mercy Fergusson tractor model 4355(3.82 Mg).The treatments were replicated three times in a randomized complete block design.Compacted plots progressively increased the bulk density from 1.63 g/cm^(3) to 1.90 g/cm^(3),but the highest bulk density was observed in plots under 15 traffic passes with the value of(1.90±0.23)g/cm3.The percentage of soil compaction varies from 90.5%to 97%at the 0-10 cm soil layer.The compression strength of soil increased from 31.00 kPa to 42.05 kPa and from 29.68 to 65.44 kPa at the 0-10 cm and 10-20 cm soil layers,respectively,which resulted in the increased shear strength from 15.79 kPa to 21.03 kPa and 14.8 kPa to 32.72 kPa at the 0-10 cm and 10-20 cm in plots under 5 and 15 traffic passes,respectively.Plot A(tilled soil)had the lowest bulk density,degree of compaction and compression strength with values(1.51±0.19)g/cm^(3),88.2%,and(12.15±0.37)kPa,respectively,and consequently the lowest shear strength of(6.02±1.23)kPa,which enhanced air movement and microbial activities in the soil.Soil under 15 traffic passes,especially at the 10-20 cm soil layer,may result in poor root penetration when cropped but can be very reliable and consistent when used for structural purposes. 展开更多
关键词 soil compaction TILLAGE degree of compaction compression strength shear strength farm machine traffic passes bulk density
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Evaluation of heavy roller compaction on a large-thickness layer of subgrade with full-scale field experiments 被引量:1
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作者 Shu-jian WANG Hong-guang JIANG +7 位作者 Zong-bao WANG Yu-jie WANG Yi-xin LI Xue-yu GENG Xin-yu WANG Kai WANG Yi-yi LIU Yan-kun GONG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2022年第11期933-944,共12页
Subgrade construction is frequently interrupted due to precipitation,soil shortage,and environmental protection.Therefore,increasing the thickness layer is required to reduce construction costs and to allow highways t... Subgrade construction is frequently interrupted due to precipitation,soil shortage,and environmental protection.Therefore,increasing the thickness layer is required to reduce construction costs and to allow highways to be placed into service earlier.This paper presents a series of full-scale field experiments evaluating the compaction quality of gravel subgrade with large-thickness layers of 65 cm and 80 cm using heavy vibratory rollers.An improved sand cone method was first proposed and calibrated to investigate the distribution of soil compaction degree across the full subgrade depth.Results showed that dynamic soil stresses caused by the heavy vibratory rollers were 2.4–5.9 times larger than those of traditional rollers,especially at deeper depths,which were large enough to densify the soils to the full depth.A unified empirical formula was proposed to determine the vertical distribution of dynamic soil stresses caused by roller excitation.It was demonstrated that soils were effectively compacted in a uniform fashion with respect to the full depth to 96.0%–97.2%and 94.1%–95.4%for the large-thickness layers of 65 cm and 80 cm within 6 or 7 passes,respectively.Empirically,linear formulae were finally established between soil compaction degree and the subgrade reaction modulus,dynamic modulus of deformation,dynamic deflection,and relative difference of settlement to conveniently evaluate the compaction qualities.It is demonstrated that increasing the thickness layer by means of heavy rollers can significantly reduce the cost and time burdens involved in construction while ensuring overall subgrade quality. 展开更多
关键词 Highway subgrade Heavy vibratory roller Thickness layer Dynamic soil stress compaction degree compaction quality control
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Degrees of Fuzzy Compactness in I-Fuzzy Topological Spaces
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作者 李宏艳 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2008年第4期999-1006,共8页
In this paper, the concept of degree of fuzzy compactness in I-fuzzy topological spaces is introduced by means of inequation. Its properties are discussed.
关键词 I-fuzzy topology value set of fuzzy compactness degrees of fuzzy compactness.
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A system and analytical method for testing the electrical parameters of soil
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作者 Yue Han Ailan Che Shaokong Feng 《Transportation Safety and Environment》 EI 2021年第1期57-71,共15页
The electrical parameters of the rock and soil are closely related to the physical parameters.By measuring the resistivity and polarizability of rock and soil reasonably,information on physical parameters such as mois... The electrical parameters of the rock and soil are closely related to the physical parameters.By measuring the resistivity and polarizability of rock and soil reasonably,information on physical parameters such as moisture content,pore ratio and compaction degree can be obtained.A system for testing the electrical parameters of soil samples based on the middle step quadrupole method is developed in this article.The system uses a series of copper needles as the electrodes of the soil-mounted test tube,and uses a multi-point multi-layer test method for layered data acquisition,which can solve the problems caused by the capacitance phenomenon and the heterogeneity of the soil sample.At the same time,factors affecting the test results,such as uneven soil preparation and water addition and electrode disturbance,are regarded as noise.A data-analysis method based on median filtering is proposed to process and analyse the test results,and the relationships between resistivity,polarizability,moisture content and compaction degree of the sample are obtained.The results show that the resistivity decreases nonlinearly as moisture content increases,and the correlation with compaction is not strong;the polarizability increases as moisture content increases with fluctuation,and it first increases and then decreases with an increase in compaction. 展开更多
关键词 testing system for electrical parameters median filtering electrical resistivity POLARIZABILITY moisture content compaction degree
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