Study on the Difference between Turfy Soil and Normal Peat Soil in China

2011 ◽  
Vol 105-107 ◽  
pp. 1551-1554 ◽  
Author(s):  
Yan Lv ◽  
Lei Nie ◽  
Kai Xu ◽  
Zhan Dong Su
Keyword(s):  
Peat Soil ◽  
Specific Weight ◽  
High Water ◽  
Structural Features ◽  
Organic Content ◽  
Engineering Properties ◽  
High Water Content ◽  
Consolidation Coefficient ◽  
The Difference ◽  
High Organic Content

As the special soil, turfy soil and peat soil in China contained some similar properties with high void ratio, high water content, high organic content, etc. But turfy soil also had properties which difference from peat soil. In this paper, based on the formation of the cause and geological environment and geomorphologic characteristics of geological in the quaternary, took the typical and widespread turfy soil and peat soil regions for example, systematically discussed the material composition and macroscopic and microcosmic structural features, put further research on the physical chemistry mechanical characteristics. Then the come to the conclusion that the essential reason for difference between turfy soil and peat soil were decomposition degree and organic content. The result that worse engineering properties such as higher the moisture content, porosity, compressibility, internal cohesion and the lower specific weight, consolidation coefficient and permeability were due to the lower decomposition degree and higher organic content of turfy soil than peat soil. It can provide reference to the practical projects of turfy soil to distinguish peat soil according to this characteristic.

Analysis on Rheological Properties of Peat Soil in Kunming Area

2012 ◽  
Vol 204-208 ◽  
pp. 722-726
Author(s):  
Yi Peng Guo ◽  
Xiao Nan Wang ◽  
Zheng Fa Lai ◽  
Jun Qing Lv
Keyword(s):  
Rheological Properties ◽  
Stress Level ◽  
Peat Soil ◽  
Strain Curve ◽  
High Water ◽  
Engineering Properties ◽  
Dianchi Lake ◽  
High Water Content ◽  
Peat Soils ◽  
Loading And Unloading

Kunming area is adjacent to Dianchi Lake. Peat soil with high water content and high compressibility is widely distributed, rheological properties is one of the most important engineering properties of peat soil. However, compared with the peat soils in the other areas, the peat soil in Kunming area has different properties. This paper studied rheological properties of peat soil in Kunming area by using the creep test of loading and unloading, on the basis of the strain-time curves, parting linear visco-elasticity, linear visco-plasticity and nonlinear visco-plasticity from the total deformation. Research shows that: ①The deformation is mostly composed of unrecoverable deformation and there is instantaneous elastic strain, instantaneous plastic strain in total strain; ②In low stress level,the soil is rendered as visco-elasticity. However, when the stress level is high, the performance of soil is visco-plasticity; ③By stress-strain curve clusters, yield stress of peat soil is approximate to 3.6 kPa in Kunming; ④Along with the time, modulus of linear visco-elasticity tended to be stable.

scholarly journals A Subglacial Boundary-layer Regelation Mechanism

1990 ◽  
Vol 36 (124) ◽  
pp. 263-268 ◽  
Author(s):  
E.M. Shoemaker
Keyword(s):  
Boundary Layer ◽  
Heat Input ◽  
High Water ◽  
Low Pressure ◽  
Critical Value ◽  
High Water Content ◽  
Overburden Pressure ◽  
Basal Ice ◽  
The Difference ◽  
Linear Nature

AbstractHeat input to basal ice at subglacial low-pressure regions, such as exist on the lee side of bed bumps including regions of ice-bed separation, is shown to melt basal ice internally in a narrow boundary layer at most centimeters thick. Before ice at the ice-bed interface can begin to melt, the heat input Q must exceed a critical value Q*. Q* increases rapidly with an increase in the difference ΔΡ between the nominal (global) overburden pressure and the magnitude of the (local) normal stress acting between the ice and bed or ice and water pocket. Because of the non-linear nature of the flow law, the thickness of the boundary layer decreases rapidly with increasing ΔΡ. The ice in the boundary layer is likely to be soft with a high water content. Under certain conditions, a regelation cycle may exist between the boundary layer and the water in a subglacial cavity. The boundary layer is sufficiently narrow that the processes can reach steady state while ice traverses subglacial low-pressure regions of length the order of 0.01–0.1 m. The regelation phenomenon may preserve or aid the formation of narrow debris-rich ice layers at the base of temperate glaciers.

High water content versus low water content—Does monthly replacement affect the difference?

1995 ◽  
Vol 22 (9-10) ◽  
pp. 198-202 ◽  
Author(s):  
Daniel Wild ◽  
Ross Grant ◽  
Tim Grant ◽  
Bill Long
Keyword(s):  
Water Content ◽  
High Water ◽  
High Water Content ◽  
The Difference

scholarly journals Ultrasoft Ground Treatment of Vacuum Preloading Combined with Calcium-Based Flocculants

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jin-Kai Yan ◽  
Feng Ji ◽  
Xia Bian ◽  
Gui-Zhong Xu ◽  
Lei Liu ◽  
...  
Keyword(s):  
Transmission Rate ◽  
Threshold Value ◽  
High Water ◽  
Soil Strength ◽  
Frame Structure ◽  
Vacuum Pressure ◽  
Engineering Properties ◽  
High Water Content ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains

Vacuum preloading is one of the popular methods improving the engineering properties of slurry ground with high water content. Commonly, the efficiency of vacuum preloading gradually decreased due to the clogging of prefabricated vertical drains (PVDs) and the low-vacuum transmission rate inside slurry. Thus, the calcium-based flocculants were used to accelerate the dewater capacity and enhance the soil strength during vacuum preloading. This paper performed a series of model tests to investigate the effect of calcium-based flocculants on the efficiency of vacuum preloading. It is found that the vacuum transmission rate was significantly improved by flocculants in comparison with raw slurry. Accordingly, the after-treatment undrained shear strength increased with the vacuum pressure, while the after-treatment water showed a decrease trend. This suggests that the increase of vacuum transmission rate inside the slurry due to the calcium-based flocculants was the main reason for the improvement of efficiency of vacuum preloading. In addition, there existed an optimal flocculants amount, where the vacuum pressure increased with flocculants’ amount up to this threshold value, followed by a decrease in vacuum pressure. This means that, at lower flocculants amount, the increase in soil flocs due to flocculation effect tended to refine the net-frame structure and water flow path, leading to an increase in the efficiency of vacuum preloading. When exceeding the optimal amount, overdosage of flocculants resulted in the clogging of PVDs due to large cemented soil particles, reducing the vacuum transmission rate inside the slurry. Hence, the after-treatment soil strength decreased with flocculants’ amount when it is higher than the optimal value.

A method to estimate the pre-eruptive water content of basalts: Application to the Wudalianchi–Erkeshan–Keluo volcanic field, Northeastern China

2020 ◽  
Vol 105 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Yankun Di ◽  
Wei Tian ◽  
Mimi Chen ◽  
Zefeng Li ◽  
Zhuyin Chu ◽  
...  
Keyword(s):  
Water Content ◽  
Volcanic Rocks ◽  
High Water ◽  
Volcanic Field ◽  
Northeastern China ◽  
Magma Ascent ◽  
High Water Content ◽  
Silica Activity ◽  
Igneous Provinces ◽  
The Difference

Abstract Water plays an important role in the generation and evolution of volcanic systems. However, the direct measurement of the pre-eruption water content of subaerial volcanic rocks is difficult, because of the degassing during magma ascent. In this study, we developed a method to calculate the pre-eruption water content of the basalts from the Cenozoic Wudalianchi–Erkeshan–Keluo (WEK) potassic volcanic field, Northeastern China, and investigated their mantle source. A water-insensitive clinopyroxene–melt thermobarometer and a water-sensitive silica activity thermobarometer were applied to these basalts. Two pressure-temperature (P-T) paths of the ascending magma were calculated using these two independent thermobarometers, with a similar P-T slope but clear offset. By adjusting the water content used in the calculation, the difference between the two P-T paths was minimized, and the water content of the WEK melts was estimated to be 4.5 ± 1.2 wt% at a pressure range of 10.1–13.5 kbar, corresponding to depths of 37–47 km. Degassing modeling shows that during the magma ascent from below the Moho to near the surface, CO2 was predominantly degassed, while the melt H2O content kept stable. Significant H2O degassing occurred until the magma ascended to 5–2 kbar. The silica activity P–T estimates of the most primary WEK samples suggest that the magmas were generated by the melting of convective mantle, which was probably facilitated by a wet upwelling plume from the mantle transition zone. The high water content found in the WEK basalts is similar to the recent reports on Phanerozoic intraplate large igneous provinces (LIPs) and supports the presence of hydrated deep mantle reservoirs as one possible source of the LIPs.

scholarly journals Settlement Behaviour of Peat Reinforced With Recycled Waste Tyre Granules

2019 ◽  
Vol 266 ◽  
pp. 04002
Author(s):  
Nor Hazwani Md Zain ◽  
Mazlizawati Mustapha ◽  
Abdul Samad Abdul Rahman
Keyword(s):  
Ground Improvement ◽  
High Water ◽  
Organic Content ◽  
High Water Content ◽  
Moderate Load ◽  
Waste Tyre ◽  
Biological Stabilisation ◽  
Distinct Separation ◽  
Recycled Waste ◽  
Settlement Behaviour

Peat is a problematic soil for having high organic content and high water content in nature. This soil is normally avoided for construction as it shows significant primary and secondary settlement even under moderate load. Ground improvement is conducted to improve peat properties by using cement column, soil replacement, chemical and biological stabilisation and others. However, some of these methods have their drawbacks for being non-sustainable to the environment, very costly, ineffectiveness and slow result performance. Alternative method using recycled waste tyre granules is seen as an innovative approach to reduce the settlement behaviour of peat in a more sustainable way. This paper investigates the effect of waste tyre granules on the settlement behaviour of peat. One-Dimensional consolidation test is carried out on natural sample and samples added with 5 % waste tyre granules with and without addition of sand as filler. The settlement curves for all samples do not show distinct separation between primary and secondary compression stages when using Casagrande’s method. Sample which is reinforced with 5 % waste tyre granules and sand has lower compression index and swelling index compared to other samples. The coefficient of volume of compressibility for all samples is reduced with increasing stress levels.

Low-Temperature Specimen Preparations For Electron Microscopy and Their Applicability to Plant Materials

1985 ◽  
Vol 43 ◽  
pp. 616-619
Author(s):  
Richard E. Crang
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
High Water ◽  
Structural Features ◽  
High Water Content ◽  
Morphological Examination ◽  
Plant Materials ◽  
Structural Support ◽  
Means Of Transmission ◽  
Cellular Components

Progress in utilizing the technologies of low-temperature sample preparation for botanical materials in the electron microscope has notably lagged behind those of other biological specimens. To a great extent this is due to the structural features of plant materials which are frequently characterized by rigid cell walls, often with a nearly impermeable cuticle, air spaces around parenchymatous tissues, and large central vacuoles of high water content with no structural support. Freezing, or cryofixation, at its best, is capable of preserving otherwise highly labile cellular components for morphological examination by means of transmission electron microscopy. It also instantaneously stops cellular movement which may result in an unnatural distribution of cell contents and/or the formation of artifactual structures within cells. Among microorganisms, it is now believed that mesosomes in bacteria and lomasomes in many fungi may be considered artifacts caused by the slow rate of chemical fixation.

Experimental Study on Solidified Sludge with High Water Content

2011 ◽  
Vol 71-78 ◽  
pp. 4265-4268
Author(s):  
Zhe Wang ◽  
Ju Hao Hu ◽  
Li Li Yan
Keyword(s):  
Water Content ◽  
High Sensitivity ◽  
Good Deal ◽  
High Water ◽  
Engineering Properties ◽  
High Water Content ◽  
Construction Sites ◽  
Engineering Construction ◽  
Main Research ◽  
Strength Character

A good deal of high water content sludge which is produced in engineering construction, with high water content, low strength, high compressibility, low permeability, high sensitivity and other undesirable engineering properties, and often contaminated. How to deal with and make rational use of high water content sludge becomes the hot topic discussed by engineering and academia. The material used in this study is sludge with high water content from the Metro construction sites in Hangzhou. In this paper, our main research is the influences of the different contents of cement, lime, gypsum, fly-ash on the curing strength character of silt. The product structure was analyzed by XRD.

scholarly journals Peat soil mass stabilization using geopolymeric hybrid material in early age

2019 ◽  
Vol 276 ◽  
pp. 05003
Author(s):  
Gunawan Wibisono ◽  
Erwin ◽  
Alfian Kamaldi ◽  
Monita Olivia
Keyword(s):  
Fly Ash ◽  
Cement Hydration ◽  
Peat Soil ◽  
High Water ◽  
Organic Soil ◽  
Soil Mass ◽  
High Water Content ◽  
Strength Development ◽  
Initial Strength ◽  
Pozzolanic Material

Peat is an organic soil, highly compressible and has high water content. The soil needs to be stabilized chemically by incorporating binders such as cement and lime into the soil that will change the properties and soil strength. However, stabilization using cement solely is not recommended since the organic acid in peat soil could delay cement hydration process. Furthermore, mass stabilization using pozzolanic material also could improve strength development of peat soil. In this research, the pozzolanic material in the form of geopolymer hybrid or geopolymer with the addition of Ordinary Portland Cement was investigated. Geopolymer was produced by activating fly ash with a combination of NaOH and sodium silicate. OPC addition improves initial strength and assists geopolymerization at ambient temperature. Variables studied were binder content and a percentage of OPC, and percentage of fly ash. Unconfined Compressive Stress (UCS) at 7 days was measured for all specimens. Mass stabilization using fly ash geopolymer hybrid could improve strength development of peat soil.

A Discussion of the Stability of Foundation Pit or Slope with Soft Interlayer or with Back Berm

2014 ◽  
Vol 1065-1069 ◽  
pp. 96-99
Author(s):  
Hai Ying Hu ◽  
Xiao Wen Zhou ◽  
Zhi Xing Huang
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
High Water ◽  
High Water Content ◽  
Sliding Surface ◽  
Foundation Pit ◽  
Soft Interlayer ◽  
The Difference ◽  
The Stability ◽  
Slice Method

The soft soil in Pearl River Delta regions is characterized with high water content, high compressibility and low bearing capacity. Therefore, when building the structures on such foundation, it’s necessary to pay attention to the deformation and stability. The projects' practice shows that, when analyzing the stability on foundation pit or slope with soft interlayer, it should not only calculate the overall stability of the slope, but also calculate the stability or bearing capacity of the foundation. Although sometimes the stability of the slope meets the requirements, it doesn’t means that the bearing capacity of the foundation meets the requirements because of the existence soft interlayer, the limitations of the circle slice method and the difference between the sliding surface and the actual sliding surface.

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