Effects of Dry Density and Water Content on Mechanical Properties of Sand-Bentonite Buffer Material

2018 ◽  
pp. 109-123
Author(s):  
Janaka J. Kumara ◽  
Takeshi Kodaka
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Dry Density ◽  
Bentonite Buffer ◽  
Buffer Material

scholarly journals Thermal Conductivity of Compacted GO-GMZ Bentonite Used as Buffer Material for a High-Level Radioactive Waste Repository

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Gui Chen ◽  
Xue-Min Liu ◽  
Xiang Mu ◽  
Wei-Min Ye ◽  
Yu-Jun Cui ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Radioactive Waste ◽  
Water Content ◽  
Radioactive Waste Disposal ◽  
Dry Density ◽  
Gmz Bentonite ◽  
High Level Radioactive Waste ◽  
Buffer Material ◽  
High Level ◽  
Crucial Parameter

In China, Gaomiaozi (GMZ) bentonite serves as a feasible buffer material in the high-level radioactive waste (HLW) repository, while its thermal conductivity is seen as a crucial parameter for the safety running of the HLW disposal. Due to the tremendous amount of heat released by such waste, the thermal conductivity of the buffer material is a crucial parameter for the safety running of the high-level radioactive waste disposal. For the purpose of improving its thermal conductivity, this research used the graphene oxide (GO) to modify the pure bentonite and then the nanocarbon-based bentonite (GO-GMZ) was obtained chemically. The thermal conductivity of this modified soil has been measured and investigated under various conditions in this study: the GO content, dry density, and water content. Researches confirm that the thermal conductivity of the modified bentonite is codetermined by the three conditions mentioned above, namely, the value of GO content, dry density, and water content. Besides, the study proposes an improved geometric mean model based on the special condition to predict the thermal conductivity of the compacted specimen; moreover, the calculated values are also compared with the experimental data.

scholarly journals Mechanical Properties of Tailings Sample with Different Moisture Contents under Dry and Wet Cycles

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Ling-ling Wu ◽  
Yao-hui Guo ◽  
Kai-wen Tong ◽  
Lin Hu ◽  
Qing Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Moisture Absorption ◽  
Water Pressure ◽  
Hunan Province ◽  
Dry Density ◽  
Initial Water Content ◽  
Sand Sample ◽  
Stress Strain ◽  
Tailings Sand

Due to precipitation infiltration, evaporation of water, and rising and falling of the wetting line, the tailings are in a cyclical moisture absorption-dehumidification state for a long time. The mechanism of change of physical and mechanical properties of tailings during the dry and wet cycle is related to the safe operation of the entire tailings dam. In order to explore the variation of the mechanical behavior of tailings in a tailings pond in Hunan Province with the number of dry and wet cycles under different initial water content conditions, the tailings sand samples with moisture content of 6.10%, 10.40%, 14.00%, 18.20%, and 21.00% were subjected to 0 to 6 times of moisture absorption and desorption cycles at natural dry density, and then, the stress-strain relationship curves, pore water pressure, failure mode, and shear dilatancy of these samples were tested by triaxial consolidation undrained shear test. The test results showed that when the number of moisture absorption and desorption cycles increases, the strength of the tailings sand sample was weakened, and the strength tended to be stable after 3∼5 cycles. In addition, the stress-strain curve of the sample with lower water content dropped sharply. However, the pore pressure of tailings sand samples with different water contents under different wet and dry cycles all showed a phenomenon of increasing first and then decreasing in general.

Ultrasonic Velocities Measurement in Compacted Bentonite-Sand Mixtures for Saturation Level Evaluation

2018 ◽  
Author(s):  
Shun Kimura ◽  
Hideharu Takahashi ◽  
Ari Hamdani ◽  
Masanori Aritomi ◽  
Susumu Ozaki ◽  
...  
Keyword(s):  
Water Content ◽  
Water Saturation ◽  
Radioactive Waste Disposal ◽  
Saturation Level ◽  
Degree Of Saturation ◽  
Ultrasonic Velocities ◽  
Compacted Bentonite ◽  
Bentonite Buffer ◽  
Buffer Material

Compacted bentonite materials are often considered as a buffer material in the geological radioactive waste disposal. This bentonite is expected to fill up the space between the waste and the surrounding ground by swelling. Therefore, understanding the surrounding ground, i.e., groundwater behavior in bentonite, as a buffer material, is essential in order to evaluate the bentonite buffer performance and guarantee long-term safety. The monitoring system of the water saturation level in compacted bentonite is required because water content in buffer material may influence its elastic properties. In this study, the correlation between water content and elasticity in unsaturated compressed bentonite was experimentally evaluated. The evaluation was done by measuring the sound velocity of both longitudinal wave and transverse wave. As a result, it can be confirmed that ultrasonic velocities could evaluate a degree of saturation and bulk modulus of compacted bentonite.

Study on the Clay Mechanical Characteristics of “Ripping Up the Bottom” in the Yellow River

2012 ◽  
Vol 212-213 ◽  
pp. 108-112 ◽  
Author(s):  
Wen Sheng Dong ◽  
Xiu Fang Jiang ◽  
Xian Feng He ◽  
Ying Ying Zai
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Mechanical Strength ◽  
Water Content ◽  
Critical Condition ◽  
Mechanical Characteristics ◽  
Yellow River ◽  
The Yellow River ◽  
Dry Density ◽  
The Relationship

Aim to the high sandy river “ripping up the riverbed” phenomenon, by experiment, analyzing the relationship between clay dry density, water content, plasticity index and its shear strength, and its mechanical properties. Create the conditions for studying clay mechanical strength and the critical condition of “bottom tearing scour”.

scholarly journals Pengaruh Abu Cangkang Sawit Terhadap Kuat Tekan Dan Kuat Lentur Batubata

2018 ◽  
Vol 3 (1) ◽  
pp. 61
Author(s):  
Herman . ◽  
Rolly I
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical Properties ◽  
Water Content ◽  
Strength Test ◽  
Basic Material ◽  
Dry Density ◽  
Soil Mixture ◽  
Palm Shell

This research was conducted to increase the value of compreive strength by adding palm shell ash to the base soil of brick. The palm oil shell was got from the result of the disposal of  Incasari Raya Factory Damasraya. The soil as the basic material of the brick was got from the brick’s manufactory Gunung Sariak Padang. The persentage of palm shell ash in the soil mixture was 0%, 5%, 15% and 25% from the soil dry weight. The test consisted of physical properties test and mechanical properties test. The physical properties test consisted of water content test, spesific gravity test, Atterberg limit test, and grain size analysis test.The mechanical properties test consisted of compaction test, compressive strength test and flexural strength test. The water content in manufacture brick was 0,85% γd maximum on wet side optimum of the soi. All the process of the brick is manufactured with manual fabrication. The result of the test showed that the values of spesific gravity (Gs), plastic limit (PL), shrinkage limit (SL),maximum dry density, optimum of water content, and compressive strength of brick increased. Mean while the liquid limit (LL),passing of sieve no. 200 in three days care, plastic index (PI), decreased. For flexural strength, at first increased, along with addition percentage from palm shell ash, this value inclined decreased. The optimum result was got 5%        palm shell ash in the soil mixture.

scholarly journals Study Of Factors Affecting The Thermal Conductivity Of Iraqi Bentonite

2012 ◽  
Vol 9 (3) ◽  
pp. 548-553
Author(s):  
Baghdad Science Journal
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Volume Fraction ◽  
Dry Density ◽  
Factors Affecting ◽  
Compacted Bentonite ◽  
Bentonite Buffer ◽  
Buffer Material ◽  
Major Factors ◽  
Water Contents

Thermal conductivity of compacted bentonite is one of the most important properties where this type of clay is proposed for use as a buffer material. In this study, Lee's disc method was used to measure the thermal conductivity of compacted bentonite specimens. The experimental results have been analyzed to observe the three major factors affecting the thermal conductivity of bentonite buffer material. While the clay density reaches to a target value, the measurement is taken to evaluate the thermal conductivity. By repeating this procedure, a relationship between clay dry density and thermal conductivity has been established in specimens after adjusting the water contents of the bentonite by placing its specimens in a drying oven for different periods. So relationships of thermal conductivity with each of these major factors (clay density, water content, and sand volume fraction) are established in this study. The relevance of these relationships be analyzed together using experimental data on many compacted bentonites.

Study on Influence of Freeze-Thaw Cycles on the Physical-Mechanical Properties of Loess

2012 ◽  
Vol 442 ◽  
pp. 286-290
Author(s):  
Gui Quan Bi
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Water Distribution ◽  
Early Stage ◽  
Frozen Soil ◽  
Dry Density ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Filling Water

Loess foundations in seasonally frozen soil region are subject to severe effect of freeze-thaw cycles. This often results in water redistribution and structure weakening. So it is very important to study the physical-mechanical properties of loess under freeze-thaw cycles. In this paper, systematic study was carried out using freeze-thaw cycle machine. The impacts of freeze-thaw cycles on the physical-mechanical properties of loess including deformation, water distribution and dry density under the condition of filling water to loess samples were investigated. The results proved that the freeze-thaw cycles can increase the water content gradually from the bottom to the top in the loess samples under water supplied condition. The water content gradient reaches maximum at the freeze-thaw interface. The loess samples deform sharply at the early stage of the freeze-thaw cycles and then reach a stable status. The freeze-thaw cycles decrease the dry density of the loess samples gradually. The dry density at the top is lower than that at the bottom, due to more severe freeze-thaw effect at the top of the samples.

scholarly journals Optimizing the Compaction Characteristics and Strength Properties of Gravelly Soils in terms of Fine Contents

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Mingzhi Zhao ◽  
Gang Liu ◽  
Longxiang Deng ◽  
Yangang Li
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Triaxial Test ◽  
Soil Structure ◽  
Fine Particles ◽  
Strength Properties ◽  
Coarse Grained ◽  
Dry Density ◽  
Engineering Practice ◽  
Gravelly Soils

Gravelly soils are widely adopted as civil construction materials in engineering practice. Although the influence mechanism of fine contents (FCs) on the mechanical behavior of gravelly soils has been emphasized in the previous studies, few discuss the compaction and strength properties concurrently. Besides, FCs of gravelly soils were discussed separately in many cases regardless of the variation in water content. In this study, modified Proctor compaction test and medium-sized triaxial test were performed to investigate the mechanical properties of gravelly soils containing different magnitudes of fine contents. It is shown that an optimum FC exists for gravelly soils although the value of the optimum FC varies with grading curves of the coarse-grained portion. By adjusting FC in the gravelly soils, not only could the maximum dry density ρdmax be improved but also the optimum saturation degree Sropt rises significantly, and synchronously, the minimum air void ratio v a min decreases notably. Besides, fine particles are just right to fill with the voids formed by the coarse-grained skeleton for the optimum FC sample. The soil structure corresponding to the optimum FC status can be termed as a densely filled skeleton structure, which is the densest and most stable. As fine contents increase or decrease from the optimum value, soil structure will loosen and deteriorate the mechanical properties. In addition, the increase in water content has quite different effects on strength properties of gravelly soils with different FCs in a triaxial test due to the opposite effects of pore water softening and negative pore pressure strengthening. Such results are expected to provide guidance for the preparation of gravelly soils in engineering practices.

scholarly journals The Healing Process of the Joints between Buffer Material Blocks and the Influence on Solute Migration

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Rui Zhou ◽  
Yuemiao Liu ◽  
Tao Xu ◽  
Yufeng Gao
Keyword(s):  
Diffusion Coefficient ◽  
Healing Process ◽  
Design Parameters ◽  
Dry Density ◽  
Mechanical Coupling ◽  
Water Head ◽  
Bentonite Buffer ◽  
Buffer Material ◽  
External Water ◽  
And Diffusion

A set of thermo-hydro-mechanical coupling control equations was established, and the healing process of the joints between Gaomiaozi bentonite (GMZ01) buffer material blocks and the influence of the joint parameters were numerically simulated. The calculations consider the effect of joints on solute migration, the permeability and thermal conductivity of the buffer material, and the evolution of the healing effect. The effects of the joint design parameters, including the type, number, width, splicing form, and average dry density of the joint, are investigated. Studies show that, under an external water head, the joints will become hydraulic priority channels due to their higher permeability, which will shorten the saturation time of the blocks. As the bentonite gradually saturates, the swelling force compresses the joint material. This action improves the overall uniformity of the buffer material and reduces the priority channel effect. Meanwhile, the final average permeability and diffusion coefficient of the buffer material are found to mainly depend on the average dry density of the buffer material. The higher the average dry density of the buffer material is, the lower the final average permeability and diffusion coefficient are, whereas the distribution of joints and the block splicing are less affected by the average dry density of the buffer material. The findings of this study can provide a reference for the design of bentonite buffer material blocks in the repository.

Sign in / Sign up

Export Citation Format

Share Document