scholarly journals Similar Materials and Engineering Application of Cemented Sand and Gravel Dam Model

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Qihui Chai ◽  
Zongkun Li ◽  
Juan Wang ◽  
Zelin Ding ◽  
Meiju Jiao
Keyword(s):  
Model Test ◽  
Engineering Application ◽  
Coarse Sand ◽  
The Body ◽  
Normal Operation ◽  
Cemented Sand ◽  
Similarity Principle ◽  
Similar Materials ◽  
New Type ◽  
Sand And Gravel

This paper takes the cemented sand and gravel dam (CSGD) in Shoukoubao reservoir as the prototype to introduce in detail the similarity principle of model test and describe the selection steps of materials for CSG model. It has developed similar materials for CSGD model by mixing coarse sand, barite powder, gypsum powder, cement, and iron powder so as to provide reference for CSGD model test in the future. The dam model test has studied the stress distribution and displacement deformation of the dam during construction and normal operation, in order to provide experimental support for the study of failure mechanism of the CSGD and facilitate the design and construction of dams of this kind. The stress level of the body and the foundation of the model dam varied from 1/9 to 1/17 of the designed compressive strength of dam material. The results showed that CSGD is a safe new type of dams.

Experimental Study on Mechanical Characteristics of CSG Materials

2011 ◽  
Vol 243-249 ◽  
pp. 2059-2064
Author(s):  
De Gao Zou ◽  
Dong Qing Li ◽  
Bin Xu ◽  
Xian Jing Kong
Keyword(s):  
Mechanical Characteristics ◽  
Shear Failure ◽  
Triaxial Tests ◽  
Cemented Sand ◽  
Optimum Water Content ◽  
Strain Relationship ◽  
Mode Stress ◽  
New Type ◽  
Sand And Gravel ◽  
Optimum Water

Cemented sand and gravel (CSG) is a new type of dam materials. It not only can reduce the waste of resources and environmental pollution, but has the merits of both gravel and concrete. In this study, Cemented sand and gravel specimens with three cement ratios were compacted at optimum water content and cured for 14 days. Based on the consolidated drained shear triaxial tests, the mechanical properties of different proportion of CSG are studied on shear failure mode, stress-strain relationship, shear strength. Research results showed that, with the increasing of the content of cement, the peak and residual strength of CSG were improved, but the failure strains were decreased. In addition, CSG material behaves distinctly softening.

Development of New-Type Similar Materials of Geomechanics Models Test for Geotechnical Engineering

2006 ◽  
Vol 326-328 ◽  
pp. 1781-1784
Author(s):  
Qiang Yong Zhang ◽  
Wei Shen Zhu ◽  
Yong Li ◽  
X.H. Guo
Keyword(s):  
Model Test ◽  
Quartz Sand ◽  
Iron Ore ◽  
Geotechnical Engineering ◽  
High Volume ◽  
Alcohol Solution ◽  
Volume Weight ◽  
Deformation Properties ◽  
Similar Materials ◽  
New Type

Geomechanics model test can simulate the real excavation process of geotechnical engineering and the mechanics deformation properties of the rockmass prototype on the condition of meeting the similar principles. In order to conducting geomechanics model test, similar material which can meet similar mechanical properties must be used. It is only after conducting a massive mechanics experiments that a new-type similar materials called iron crystal sand is developed in this paper. This material consists of iron ore powder, blanc fix, quartz sand, gypsum powder and rosin alcohol solution which are evenly mixed in certain proportion and pressed together. The iron ore powder, blanc fix and quartz sand among them are main materials. The rosin alcohol solution is the cementing agent and gypsum powder the regulator. The material mechanics experiments show that this material has following outstanding characteristics: high volume-weight, wide variable mechanical parameters, stable performance, low price, quick drying, simple processing and innocuity. It can simulate most rockmass material from soft to hard ones and can be widely used in geomechanics model tests in fields of energy sources, transportation, water conservancy and mining.

scholarly journals Stress Characteristics and Overload Failure Analysis of Cemented Sand and Gravel Dam in Naheng Reservoir

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 950-959
Author(s):  
Zhaoqiang Wang ◽  
Xin Chen
Keyword(s):  
Numerical Simulation ◽  
Failure Mode ◽  
Model Test ◽  
Structural Model ◽  
Test Method ◽  
Distribution Law ◽  
Dead Weight ◽  
Cemented Sand ◽  
Stress And Deformation ◽  
Sand And Gravel

Abstract On the basis of the Naheng Reservoir Project, the stress, strain, and deformation of Naheng Reservoir cemented sand and gravel dam are simulated numerical simulation and structural model test. The stress and deformation laws of the dam under the combined load of dead weight and normal water level are analyzed using the structural model test method. Compared with the finite element numerical simulation, the results reflect the stress and deformation distribution law of the dam. Then, the failure mode of the cemented sand and gravel dam can be visualized by using the water load overload method to conduct the structural model failure test, and the failure mode and failure mechanism of the cemented sand and gravel dam can be discussed. The research results lay a foundation for further determining the safety degree analysis of cemented sand and gravel dam.

scholarly journals A New Type of Cemented Sand-Gravel (CSG) Mixtures for Water-Tightening of Hardfill Dams

2021 ◽  
Author(s):  
Sina Karimi ◽  
Hamed Farshbaf Aghajani
Keyword(s):  
Cement Hydration ◽  
Cement Content ◽  
Weight Ratio ◽  
Sem Images ◽  
Cemented Sand ◽  
Native Soil ◽  
New Type ◽  
Sand And Gravel ◽  
Compaction Properties ◽  
Native Soils

Abstract This paper aims to achieve a specific type of cemented sand-gravel mixtures with low permeability to implement in the impervious zone of hardfill dams. To this end, various mixtures are prepared by blending two native soils of sand and gravel with different amounts of kaolinite or bentonite additives in presence of various cement content. The compaction properties, uniaxial compressive strength, permeability and scanning electron microscope (SEM) images of mixtures are measured. According to the results, the cemented mixture containing 10% of kaolinite additive regardless of native soil type exhibits the maximum strength. However, the bentonite disturbs the cement hydration in the mixture, and the strength of mixtures especially with high cement content decreases with increasing the bentonite content. The permeability of mixtures is related to the amount of cement and fine additive in the mixture. The permeability of both cemented sand and gravel mixtures decreases with increasing the bentonite additive. However, the kaolinite additive has a limited influence on the permeability of cemented gravel mixtures. The lowest permeability is achieved in the mixture involving the higher amount of bentonite (with a weight ratio of 30%) in presence of adequate cement.

scholarly journals Statistical Law and Predictive Analysis of Compressive Strength of Cemented Sand and Gravel

2020 ◽  
Vol 27 (1) ◽  
pp. 291-298
Author(s):  
Shoukai Chen ◽  
Yongqiwen Fu ◽  
Lei Guo ◽  
Shifeng Yang ◽  
Yajing Bie
Keyword(s):  
Compressive Strength ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Predictive Analysis ◽  
Distribution Law ◽  
Data Set ◽  
Cemented Sand ◽  
Mix Proportion ◽  
Kolmogorov Smirnov ◽  
Sand And Gravel

AbstractA data set of cemented sand and gravel (CSG) mix proportion and 28-day compressive strength was established, with outliers determined and removed based on the Boxplot. Then, the distribution law of compressive strength of CSG was analyzed using the skewness kurtosis and single-sample Kolmogorov-Smirnov tests. And with the help of Python software, a model based on Back Propagation neural network was built to predict the compressive strength of CSG according to its mix proportion. The results showed that the compressive strength follows the normal distribution law, the expected value and variance were 5.471 MPa and 3.962 MPa respectively, and the average relative error was 7.16%, indicating the predictability of compressive strength of CSG and its correlation with the mix proportion.

The Study on the Ratio of Similar Material in Landslide Model Test

2011 ◽  
Vol 261-263 ◽  
pp. 1679-1684
Author(s):  
Xiao Ling Liu ◽  
Shi Mei Wang ◽  
Yun Zhi Tan ◽  
Xin Jiang Hu ◽  
Dai Peng Zhao
Keyword(s):  
Model Test ◽  
Influence Factors ◽  
Deformation Modulus ◽  
High Strength ◽  
Similar Material ◽  
Talcum Powder ◽  
Angle Of Internal Friction ◽  
Similar Materials ◽  
Mixed Material ◽  
Landslide Model

The choice of similar materials and the design of mix proportions is a key step in landslide model test. On the basis of experiment, we conduct a research for the similar materials which may sufficing volume weight, cohesive force, angle of internal friction, deformation modulus, and the infiltration coefficient on the same time. Then we put forward two kinds of schemes: one is the mixed material of high-strength glass micro beads and talcum powder; the other is the mixed material of lead beads, river sands, rubber powder and talcum powder. By analyzing the result of mix proportions test, We concluded the regularity that similar index varies along with different content of the similar material ingredients and found the notable influence factors , which provides important reference for the components of similar materials in the landslide model test.

Kropparnas poesi

2021 ◽  
Vol 51 (1-2) ◽  
pp. 5-14
Author(s):  
Anna-Klara Bojö
Keyword(s):  
Women Writers ◽  
Young Women ◽  
Literary History ◽  
The Body ◽  
Different Types ◽  
New Type

The Bodies’ Poetry: Eva Runefelt, Eva Ström and Swedish Poetry in the Late 1970’s In the mid 1970’s a new type of poetry, associated with the body, emerged in Sweden. Especially young women writers appeared to take Swedish poetry in new aesthetic directions, exploring questions regarding experience and language. This article focuses on two prominent writers, Eva Runefelt and Eva Ström, and discusses how their different types of poetry can be said to be a bodies’ poetry, and how it was discussed in contemporary literary critique. It also reflects on why this strand of poetry has been granted such a peripheral place in literary history.

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

Enhanced surface hydrophilicity of polylactic acid sutures treated by lipase and chitosan

2018 ◽  
Vol 89 (16) ◽  
pp. 3291-3302 ◽  
Author(s):  
Shuqiang Liu ◽  
Mingfang Liu ◽  
Gaihong Wu ◽  
Xiaofang Zhang ◽  
Juanjuan Yu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Friction Coefficient ◽  
Surface Area ◽  
Polylactic Acid ◽  
The Body ◽  
Optimal Conditions ◽  
Absorbable Sutures ◽  
Surgical Sutures ◽  
New Type ◽  
Enhanced Surface

Polylactic acid (PLA) surgical sutures are a new type of absorbable sutures that can be degraded and absorbed in the body. However, there is high hydrophobicity for the surface of PLA sutures, which leads to poor biocompatibility and cellular affinity. In order to increase the hydrophilicity, the PLA sutures were etched by lipase firstly, and then grafted with chitosan. The results indicate that the optimal conditions of treating PLA sutures by lipase were as follows: 45℃ reaction temperature, 4.5 g/L concentration of lipase and 8 h reaction time. The sutures were etched by lipase and then formed some grooves and a number of hydroxyl (-OH) bonds, which led to increased surface area and hydrophilicity, but a drop in mass and strength. The optimal conditions of grafting chitosan onto PLA sutures were as follows: 4 h reaction time and 3 g/L concentration of chitosan. The chitosan grafted and loaded on the surface of PLA sutures, and in some areas of the sutures the chitosan reunited, which led to a rough surface and large friction coefficient. Finally, the hydrophilicity of the PLA sutures, treated by lipase and then grafted with chitosan, was greatly improved.

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