Characteristics Of Silt Research Articles

Technology Dealing with the Soft Soil Foundation

Soft foundation is one of the important factors affecting the quality of construction in the building construction, so in order to better improve the quality of construction, we must take corresponding measures to deal effectively with this problem, mainly discusses the profound advances in treatment of soft soil subgrade, this paper probes into the combination of the characteristics of the silt along the beach area of the soft foundation treatment technology progress. Aiming at the current development process of municipal beach road construction problems, based on the analysis of deep soft soil subgrade treatment methods, introduces the recent progress in the exploration of China’s tidal silt characteristics in rock and soil engineering, combined reinforcement technology research methods, the combination of the developed new technology of deep soft foundation treatment hope can be applied to practical engineering.

Methodological features of the assessment of silting processes of artificial reservoirs based on the analogy method

The similarity of artificial reservoirs (AR) is determined by the proximity of their parameters and characteristics. In this regard, the selection of the criteria for analogy is, in fact, the task of multicriteria comparative analysis, which dictates the need, on the one hand, to select the parameters of artificial reservoirs to a decisive degree, determining those characteristics of the reservoirs that reflect their studied properties and, accordingly, the synthesis of the criteria for analogy , providing a solution to the problem of choosing a reservoir-prototype for the analyzed reservoir-analogue. A methodology for estimating the process of siltation of artificial reservoirs (analogues) based on known silt characteristics of a specially selected prototype reservoir is developed. The criterion for choosing a reservoir prototype is a measure of analogy, calculated on the basis of the main characteristics - morphological, hydrological, physico-chemical and biological compared reservoirs. The method is based on the use of sets of complex criteria of various levels of completeness determined by the number of particular criteria included in the complex criterion with the corresponding weight coefficients on the basis of the maximum level of analogy, which is determined by a special measure - the coefficient of nonconformity or the inverse coefficient of analogy. The latter is defined as the ratio of the difference between the criteria for the analogy of the reservoirs being compared to their mean value. A comparative analysis of the values of similarity criteria for reservoirs - analogues (cascade reservoirs) and a reservoir - a prototype and a comparative analysis of the values of the similarity criterion for all combinations of pairs of reservoirs of the Dnieper cascade. On this basis, a matrix of differences in the reservoirs of analogues is constructed, which makes it possible to estimate the possibility of using the similarity method, using as an analogue one of the reservoirs of the cascade, if it satisfies the requirements of analogy.

Coupled influence of content, gradation and shape characteristics of silts on static liquefaction of loose silty sands

Static liquefaction is a challenging problem of geotechnical engineering as its consequences are generally catastrophic when they occur on site. Previous laboratory studies focused on various factors that could influence the static liquefaction potential of silty sands. Most popular of those investigated factors are stress conditions, deposition method and fines content. The purpose of the present study is to investigate the other possible factors, of which very little is known, mainly focusing on the silt characteristics including grain size distribution, relative size, and shape effects of the silt grain matrix within the sand. Undrained monotonic triaxial compression tests were conducted on thirty sands with varying fines contents, which were prepared by mixing three base sands (Sile Sands 20/30, 50/55, 80/100) with same geologic origin but with different gradations and three different non-plastic silts (IZ, SI and TT silts) with different gradations and shape characteristics. The experimental results revealed that each of the mentioned factors had their own influence on static liquefaction behavior of sands. The static liquefaction potential of all the three sands in this study was observed to increase with decreasing coefficient of uniformities of the silt grain matrix (CUsilt) in sands. For a particular base sand, static liquefaction potential was observed to increase with decreasing mean grain diameter ratio (D50-sand/d50-silt) due to change of silt gradation. However, shape characteristics of the silt grains are also found to be another important factor, in certain cases observed to have a greater influence than mean grain diameter ratio criterion. As an example, it was shown that at the same FC, base sand, depositional energy and consolidation stress, angular nature of TT silt potentially caused more meta-stable contacts (weaker grain contacts that promote excess pore pressure generation during shearing) within the specimens than sub-rounded SI silt, which caused specimens with TT silt to be more liquefiable than their counterparts with SI silt. Moreover, it was found that there is a coupled relationship between the fines content and investigated silt characteristics (gradation, mean size, shape effects) on the static liquefaction behavior of sands. The unexpected trend regarding the last finding is that the mentioned influence of silt characteristics (i.e. gradation, size and shape) on static liquefaction of sands becomes more considerable with decreasing fines content at loose states.

Swelling Behavior of Montmorillonites Noncolloidally Crosslinked with ε‐Al13

Core Ideas The expansion properties of montmorillonites treated with PHA steeply decreased. A mixture of montmorillonites and PHA solution is not a colloidal system. Al13 groups are the main intercalator and factor influencing swelling behavior. The treatment may be applied in expansive soil research. Studies concerning noncolloidally crosslinked montmorillonites (NCMs) are significant for the chemical treatment of expansive soil. In this study, NCMs with OH/Al molar ratios of 1.0, 1.5, 2.0, and 2.5 and Al/montmorillonite ratios of 0.1, 0.3, 0.5, 0.8, and 1.0 mmol g−1 were prepared via AlCl3–NaOH reactions and subsequent Al13–montmorillonite interactions. The resulting NCMs exhibited the characteristics of silt as well as significant expansion and mechanical property changes. The expansion properties of the NCM samples, including the free swelling ratio, swelling force, free expansion ratio, and expansion ratio under 50 kPa all decreased significantly. According to the X‐ray diffraction data, the basal spacing of the NCM samples became relatively stable and slightly expanded after the drying and rewetting processes. Additionally, the cohesive force and shear strength of the NCM samples increased significantly after the crosslinking process. Furthermore, the X‐ray fluorescence spectrometry results confirmed that the Al oxide content of the NCMs increased as the swelling properties decreased, indicating that primarily the Al13 groups influenced the swelling behavior of the NCMs.

Particle Flow Simulation on Collapse Characteristics of Silt Under Mutation of Principal Stress Orientation

The behaviors of granular material and influencing factors under complex dynamic loading are studied by more and more researchers with particle flow method. Only the strain-controlled loading has been generally used in the current study, although this method was not consistent with the practice of engineering in many situations. In this article, stress-controlled dynamic simulation tests were carried out with particle flow method, which were used to study the collapse characteristics of silt under mutation of principal stress orientation. The tests were performed by PFC2D. The simulation results and the laboratory real tests’ results had a high degree of similarity, particularly in the collapse strain and vibration times. It was very useful to forecast the silt's critical failure state. Based on the verification data, the effects of confining pressure and cyclic shear stress ratio on the collapse characteristics of silt were studied further. With the increase of cyclic shear stress ratio, the deviator strain amplitude increased and the required vibration times gradually reduced to achieve the same strain level. Under the same dynamic shear stress ratio and vibration times, the initial dynamic elastic modulus slightly increased with the increase of initial confining pressure, and the variation range of final collapse deviator strain was small. In the analysis of micro-structural evolution, the redistribution of internal stress of sample was revealed during cyclic loading. With the increase of vibration times, the development of distribution gradually stabilized, and then the high shear stress appeared in some connected regions. On that stage, the particle system developed to instability and failure. The PFC simulation results confirmed that the collapse state was the critical stage to trigger the liquefaction of silt.

Effect of Treatment with Cement on the Mechanical Characteristics of Silt from Telagh Region of Sidi Belabes, Algeria

In Algeria the use of soil treated with hydraulic binder is not responded because the very few sites already completed have not experienced feedback to confront the knowledge on the subject. Most soils in their natural condition lack the strength, dimensional stability and durability required for building. These inherent deficiencies may be overcomed through a process of stabilization by mechanical compaction and addition to the soil matrix of chemical binders, such as cement or lime. High water content and low workability of local soils have often caused difficulties for highway construction projects. The addition of a few percentages by weight of cement has shown its effectiveness towards better control of workability during compaction and significant cost savings over removal and replacement of backfill material in some projects (Sariosseiri and Muhunthan in Eng Geol 104:119–125, 2009). This paper is focused on understanding the compaction characteristics and mechanical properties of compacted cement stabilised soil mixtures. We opted to base our work on a laboratory study, conducting soil–cement mixtures. A soil area Telagh was treated with cement varying each time the quantities of cement and water, in order to observe the influence of dosage and the amount of water present in the mixture on compressive strength and the stiffness of the material. In this study, natural silty soil extracted from the locality Guetna of region “Telagh” was characterized and mixed with cement to prepare compacted cylindrical samples to standard Proctor (OMC) of different cement doses and different water–cement ratios. After curing, the hardened samples were tested and their compressive strength was investigated for different duration. Another important parameter is considered in this study is the extent of the permeability of the soils treated with cement, as our material can be used for building dams and dykes. The results of the first part of this study showed the influence of cement content on compaction characteristics and water permeability of stabilized Guetna soil. The results from the second part of this study showed the effect of time lag, water–cement ratios, and dosage of cement on the compressive strength and elastic modulus of the investigated. Salient conclusions of the study are (a) compaction characteristics of soils are affected by the addition of cement, in particular the water content that increases with high doses of cement, (b) compressive strength increased with dosage of cement varying to 2 % at 6 %, even at lower values of cement doses, (c) in contrast, the water contact on soil leads to a marked decrease in compression strength, (d) the results also indicated that the water permeability decrease when le cement content increased, (e) the elastic modulus defined at 50 % of peak strength is determined for studied material at different binder contents and different curing times, (f) the development of elastic modulus is in accordance with compressive strength. A quantitative correlation E50 = 75. Rc is therefore determined according to large quantities of test results.

The Experiment Study on Parameters of Duncan-Chang Model for Silt Based on Different Water Content

Duncan-Chang model can reflect soil’s nonlinear behavior much better, its’ concept is clear and easy to understand. In this paper, through triaxial test, parameters of Duncan-Chang model were gained by analyzing characteristics of Silt’s stress-strain Cures. A key factor, effecting silt’s stability, is the moisture content; there is a optimum moisture content in silt, in this moisture content, silt’s parameters of Duncan-Chang model can reach to the optimal state.

Research Progress of Sintered Wall Material Products Synchronous Cutting Machine

By means of raw performance analysis of silt sintered porous brick, the importance of synchronous cutting machine in the molding process was revealed. On basis of the analysis of the present situation of research and application of synchronous cutting machine at home and abroad, according to the forming characteristics of silt sintered porous brick, technical parameters of synchronous cutting machine was explained and the development trend of the synchronous cutting machine was expected.

Strength and deformation characteristics of compacted silt from the lower reaches of the Yellow River of China under monotonic and repeated loading

Silt is a widespread deposit in the lower reaches of the Yellow River, China with low plasticity and cohesion and poorly-graded characteristics. It is the primary filling material for subgrades in this region because of the lack of sand and gravel materials. Using the California Bearing Ratio (CBR) method alone to characterize the silt subgrade cannot provide an adequate assessment of its shear behaviors under monotonic and repeated loading. To improve the understanding of the strength and deformation characteristics of silt fill, a series of triaxial tests under monotonic and repeated loading were conducted. Specifically, the variations in the engineering characteristics (such as shear strength, permanent deformation, resilient modulus, and threshold stress) of silt fill caused by changes in the physical and stress states were investigated. Experimental results were used to establish empirical correlations for the strength and deformation parameters. These results provide a basis for the mechanical analysis and design of silt subgrades for stability.

증기추출법과 결합된 공기주입법을 이용한 비수용성액체 해양퇴적물의 TPHs, TCE, PCE 및 BTEX 정화

이 연구는 공기주입법(in-situ air sparging; IAS)이 결합된 증기추출법(vapor extraction; VE)을 이용한 실내 실험 연구로 비수용성액체 유기물(non-aqueous phase liquids; NAPLs)의 총유류계탄화수소(total petroleum hydrocarbons; TPHs), 트리클로에틸렌(trichloroethylene; TCE), 퍼클로로에틸렌(perchloroethylene; PCE), 벤젠(benzene), 톨루엔(toluene), 에틸벤젠(ethylbenzene) 및 크실렌(xylenes)을 제거하기 위한 목적으로 국내 만돌, 하전, 상암, 부산만내 해양 퇴적물들을 대상으로 실험 하였다. 만돌 퇴적물은 사질(sand; S) 특성(평균입도 1.789 <TEX>${\Phi}$</TEX>), 하전은 모래실트(sandy Silt; sZ) 특성(평균입도 5.503 <TEX>${\Phi}$</TEX>) 및 상암은 실트(Silt; Z) 특성(평균입도 5.835 <TEX>${\Phi}$</TEX>)을 나타내었다. 그리고 부산지역 퇴적물은 점토(Clay; C) 특성(평균입도 8.528 <TEX>${\Phi}$</TEX>)을 나타내었다. 48시간 동안 공기를 주입하지 않은 B1 (0 L/min) 컬럼에서 남아있는 TPHs는 만돌, 하전, 상암지역 및 부산지역 샘플퇴적물에서 각각 약 2,459, 6,712, 4,348, 14,279 ppm으로 분석 되었다. 그리고 만돌, 하전, 상암지역 및 부산지역 샘플퇴적물의 B2 (3 L/min)-B5 (5 L/min) 컬럼에서 TCE는 99.5-100.0% 제거되었으며, PCE는 93.2-100.0%까지 제거된 결과를 보였다. 입자크기에 따른 각 성분의 제거량과의 상관관계는 TCE, PCE, toluene, etylbenzene, xylene, BTEX에서 모두 0.90-0.99의 밀접한 상관계수를 보였다. 그러나 TPHs에서는 0.76, Benzene에서는 0.71의 낮은 상관계수를 보였다. This study was carried out in order to determine the remediation of total petroleum hydrocarbons (TPHs), trichloroethylene (TCE), perchloroethylene (PCE), benzene, toluene, ethylbenzene and xylenes (BTEX) compounds for non-aqueous phase liquids (NAPLs) using in-situ air sparging (IAS) / vapor extraction (VE) with the marine sediments of Mandol, Hajeon, Sangam and Busan, South Korea. Surface sediment of Mandol area had sand characteristics (average particle size, 1.789 <TEX>${\Phi}$</TEX>), and sandy silt characteristics (average particle size, 5.503 <TEX>${\Phi}$</TEX>), respectively. Sangam surface sediment had silt characteristics (average particle size, 5.835 <TEX>${\Phi}$</TEX>). Sediment characteristics before experiment in the Busan area showed clay characteristics (average particle size, 8.528 <TEX>${\Phi}$</TEX>). TPHs level in the B1 column of Mandol, Hajeon, Sangam, and Busan sediments were 2,459, 6,712, 4,348, and 14,279 ppm. B2 (3 L/min) to B5 (5 L/min) columns reduced 99.5% to 100.0% of TCE and 93.2% to 100.0% of PCE. Removal rates of TCE, PCE, and BTEX are closely correlated (0.90-0.99) with particle sizes and organic carbon concentrations. However, TPHs (0.76) and benzene (0.71) showed the poorer but moderate correlations with the same parameters.

SHEAR CHARACTERISTICS OF SILT CONTAINING SAND

SHEAR CHARACTERISTICS OF SILT CONTAINING SAND

MINERALOGICAL AND CHEMICAL COMPOSITION OF THE SILT FRACTION OF SOME SOILS, SOIL-BUILDING ROCKS, AND DISPERSED MATERIAL OF RIVERS IN THE KURA-ARAXES LOWLAND

The physical, mineralogical, and chemical properties of soils, soil-building rocks, and dispersed materials of rivers in the Kura-Araxes lowland, U. S. S. R. , are dependent upon the quantity and quality of organic substances contained, distribution and characteristics of silt and colloidal fractions, and amount and composition of bases and salts absorbed in the soils. These characteristics affect swelling, maximum hygroscopic capacity, and hardness. Iron-oxide films on the surfaces of micro-aggregates increase soil stability, essentially maintained by capillary forces and by swelling of hydrophilic colloids. During irrigation, soils increase in volume; nonstructured soils become packed when dry. Crust building involves soil swelling, soil-lump soaking and destruction by enclosed or adsorbed air, soil packing, and hardening with simultaneous shrinkage and cracking. Slow irrigation along furrows, subsoil irrigation, and rain-making are recommended for the prevention of crust building, as are other general agrotechnical measures. Editor