• Title/Summary/Keyword: clay-bearing materials

Search Result 21, Processing Time 0.025 seconds

A novel method for predicting the swelling potential of clay-bearing rocks

  • Moosavi, Mahdi;Ghadernejad, Saleh
    • Geomechanics and Engineering
    • /
    • v.27 no.6
    • /
    • pp.615-626
    • /
    • 2021
  • The main objective of this study is to present a fast and reliable approach to predict the swelling potential of clay-bearing rocks. Investigations showed that there is a good correlation between the swelling potential of a rock and its desire to absorb water due to its clay content which could be measured using the "Contact Angle" test as one of the most common ways to determine the wettability. In this test, the angle between a water drop and the flat rock surface on which it rests is measured. The present method is very fast and returns repeatable results and requires minimal sample preparation. Only having a saw-cut surface of a sample with any shape is all one needs to perform this test. The logic behind this approach is that the swelling potential of a rock is a function of its mineral content and molecular structure, which are not only distributed in the bulk of the sample but also reflected on its surface. Therefore, to evaluate swelling behavior, it is not necessary to wait for a sample to get wet all the way to its "internal structure" (which, due to the low permeability of clay-bearing rocks, is very slow and time-consuming). Instead, one can have a good sense of swelling potential by studying its surface. Parametric studies on the effect of moisture content, porosity, and surface roughness on the contact angle measurements showed that using a saw-cut oven-dried sample is a convenient way to evaluate the swelling potential by this method.

Iron-loaded Natural Clay as Heterogeneous Catalyst for Fenton-like Discoloration of Dyeing Wastewater

  • Xu, Huan-Yan;Ha, Xiu-Lan;Wu, Ze;Shan, Lian-Wei;Zhang, Wei-Dong
    • Bulletin of the Korean Chemical Society
    • /
    • v.30 no.10
    • /
    • pp.2249-2252
    • /
    • 2009
  • The clay-based Fe-bearing catalyst was successfully prepared through ion-exchange reaction and applied as heterogeneous catalyst for discoloration of acid fuchsine (AF) in an aqueous solution by Fenton-like reaction. Experimental results demonstrated that the AF discoloration ratios increased by increasing Fe-loaded clay dosage and initial $H_2O_2$ concentration, and by decreasing the pH, respectively. The lower the initial AF concentration, the shorter the reaction time needed to achieve complete discoloration of AF. Comparative studies indicated that AF discoloration ratios were much higher in presence of Fe-loaded clay and $H_2O_2$ than those in presence of $H_2O_2$, raw natural clay or Fe-loaded clay only and raw natural clay and $H_2O_2$ jointly. After AF discoloration, there existed no new phases in the clay samples detected by XRD and no change in the clay crystal morphology observed by SEM. A mechanism proposed suggested adsorption and Fenton-like reaction were responsible for discoloration of AF.

Dehydration by Electro-osmosis on Ceramic Body (Electro-osmosis에 의한 Dehydration)

  • Han, Sang-Mok
    • Journal of Industrial Technology
    • /
    • v.4
    • /
    • pp.43-46
    • /
    • 1984
  • In process of water removing safely from plastic clay, an electric field applied to a wet, porous solid such as day usually causes the rapid dehydration. The water-bearing positive ions move to negative electrode under the d. c. electrical stress or field. Therefore application of electro-osmosis to wet clay could include drying thick and large-scale ceramic body quickly and evenly. The d. c. power supply unit to 60 volts is necessary for safe practice. Also wider contact area and shorter distance between electrodes accelerate effectively the removal of water.

  • PDF

A Study on the Soil Architecture (흙건축에 관한 연구)

  • Lim, Sang-Hoon;Suh, Eung-Chul
    • KIEAE Journal
    • /
    • v.2 no.2
    • /
    • pp.45-50
    • /
    • 2002
  • In the last century, mainly our cultures destroyed a lot of ourselves as well as of our natural environment by deterioration, pollution and exploitation. Building activities are for a third responsible for these disasters and they are fully the reason for the growing Sick Building Syndrome. In result, Materials of the building should be derived as much as possible from nature, and walls should be made of yellow soil, or of bricks made from yellow soil The adobe can easily have larger or smaller dimensions, and different thickness as weil, according to the purpose for which they are meant, and the structural load-bearing function they have to fulfill. In spite of the importance of clay, research or experiment of clay has been quite weak. However, in stead of endowing the clay with the value as natural architectural material, we want to evaluate it as an important element of the environment.

ROLE OF SOILS IN THE DISPOSAL OF NUCLEAR WASTE

  • Lee, S.Y.
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.19 no.3
    • /
    • pp.251-268
    • /
    • 1986
  • Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

  • PDF

Characteristics of Settlement and Bearing Capacity of Soft Ground Improved by Granular Pile (Granular Pile에 의해 개량된 연약지반의 지지력 및 침하특성)

  • 천병식;여유현
    • Proceedings of the KSR Conference
    • /
    • 2002.05a
    • /
    • pp.289-294
    • /
    • 2002
  • Sand Compaction Pile (SCP) method, which uses sand material, is frequently used in Korea. However, the use of sand for SCP faces environmental and economical problems with the shortage of its resources. Therefore, it is necessary to substitute other materials for compaction piles. One of the alternatives is using gravel in lieu of sand. Granular Pile, constituted with sand and crushed-stone, is one of the methods to improve soft clay and loose sandy ground. In this study, modeled pile load tests are performed in test cell. The observations are made on the consolidation and the variation of water table of three different grounds, original, sand pile installed, and granular pile installed ground. In addition, engineering characteristics such as bearing capacity, settlement and drainage are investigated. The test results show that Gravel Compaction Pile (GCP) is more efficient for increasing bearing capacity and reducing settlement than SCP and had similar pore water pressure dissipation to sand. Therefore, the results show that GCP can be a good substitution for SCP.

  • PDF

Study on mechanical properties of phosphate tailings modified clay as subgrade filler

  • Xiaoqing Zhao;Tianfeng Yang;Zhongling Zong;Teng Liang;Zeyu Shen;Jiawei Li;Gui Zhao
    • Geomechanics and Engineering
    • /
    • v.36 no.6
    • /
    • pp.619-629
    • /
    • 2024
  • To improve the utilization rate of phosphate tailings (PTs) and widen the sources of subgrade filler, the PTs is employed to modify clay, forming a PTs modified clay, applied in the subgrade. Accordingly, the environmental friendliness of PTs was investigated. Subsequently, an optimal proportion was determined through compaction and California Bearing Ratio (CBR) experiments. Afterward, the stability of mixture with the optimal proportion was further evaluated through the water stability and dry-wet stability experiments. Finally, via the gradation and microstructure experiments, the strength mechanism of PTs modified clay was analyzed. The results show that the PTs were classified in the non-hazardous solid wastes, belonging to Class A building materials. With the increase of PTs content and the decrease of clay content, the optimum water content and the swelling degree gradually decrease, while the maximum dry density and CBR first increase and then decrease, reaching their peak value at 50% PTs content, which is the optimal proportion. The resilient modulus of PTs modified clay at the optimal proportion reaches 110.2 MPa. The water stability coefficient becomes stable after soaking for 4 days, while the dry-wet stability coefficient decreases with the increase of cycles and tends to be stable after 8 cycles. Under the long-term action, the dry-wet change has a greater adverse impact than continuous soaking. The analysis demonstrates that the better strength mainly comes from the skeleton role of PTs and the cementation of clay. The systematic laboratory test results and economic analysis collectively provide data evidence for the advantages of PTs modified clay as a subgrade filler.

The Analysis of Bearing Capacity Behavior of Strip Footing on Geogrid-Reinforced Sand over a Soft Clay by Numerical Method (수치해석방법에 의한 연약지반위의 보강띠기초의 지지력거동해석)

  • Kim, Young-Min;Kang, Seong-Gwi
    • Journal of the Korean Geosynthetics Society
    • /
    • v.8 no.3
    • /
    • pp.1-7
    • /
    • 2009
  • Earth reinforcement by using geogrids as reinforcing materials are widely applied to several earth structures. The bearing capacity of geogrid reinforced foundation soils is usually examined on based on the rigid plasticity theory or Limit Equilibrium Method. Method of analysis such Limit Equilibrium Method provide no detail information about failure behaviour or strain which develop in the reinforcement or foundation. In this paper the analysis of failure behaviour of strip footing on geogrid-reinforced sand over a soft caly was investigated by using a numerical method. A series of finite element analyses were performed on a geogrid-reinforced strip footing over a soft clay including number of geogrid layers, length, depth. We effectively investigated the failure behaviour and improvement of bearing capacity on the reinforced foundation soil by using FEM program.

  • PDF

Pressuremeter Test in YULCHON Combined Cycle Power Plant (율촌 복합화력발전소 공내 재하 시험)

  • Lee, Yong-Gil;Park, Kyung-Ho
    • Journal of the Korean GEO-environmental Society
    • /
    • v.2 no.1
    • /
    • pp.5-13
    • /
    • 2001
  • The purpose of this paper is to present the pressuremeter test result and analysis for Yulchon Combined Cycle Power Plant(CCPP) site. The CCPP site is old backfill area with the hillcut materials obtained from the borrow sources near the mountains. The geology of this area consists of 6-layers from the ground level such as hillcut material, dredged clay fill, silty sand, original marine clay, weathered rock, soft rock, etc.. The pressuremeter test has been carried out with three different probe, in size and membrane type for all layers except the clay layers. The cone penetration test has been also carried out to collaborate with the pressuremeter test in the hillcut material layer.

  • PDF

Investigation of engineering properties of clayey soil experimentally with the inclusion of marble and granite waste

  • Baki Bagriacik;Gokhan Altay;Cafer Kayadelen
    • Geomechanics and Engineering
    • /
    • v.34 no.4
    • /
    • pp.425-435
    • /
    • 2023
  • Granite and marble are widely produced and utilized in the construction industry, resulting in significant waste production. It is essential to manage this waste appropriately and repurpose it in recycling processes to ensure sustainability. The utilization of waste materials such as marble and granite waste (MGW) has become increasingly important in geotechnical engineering to improve the physical and mechanical properties of weak soils. This study investigated the applicability of utilizing MGW and cement (C)-MGW mixtures to improve clayey soil. A series of model plate loading tests were carried out in a specialized circular test tank to assess the influence of MGW and C-MGW mixing ratios on clayey soil samples. The samples were prepared by blending MGW and C-MGW in predetermined proportions. It is found that the bearing capacity of clay soil increased by approximately 71% when using MGW and C additives. Moreover, the consolidated settlement values of the clay soil decreased up to 6 times compared to the additive-free case.