Discussion on Design and Construction of Soil and Foundation in Coastal Saline Soil Area

2011 ◽  
Vol 90-93 ◽  
pp. 645-650
Author(s):  
Fu Ju Gao

Based on the recent 20 years' observation and research, this paper briefly discusses the mechanism of forming, mechanical properties of coastal saline soil and the main factors which bring the important influence to buildings. Some reasonable comments on design and construction of the work in this area are put forward.

2015 ◽  
Vol 744-746 ◽  
pp. 641-646
Author(s):  
Bi Hong Song ◽  
Cong Han ◽  
Jian Hua Chen ◽  
Xue Li Shan ◽  
Chun Yan Wang

The design scheme and engineering construction technology are proposed for an accommodation highway subgrade on the basis of forming reasons and hazard analysis of saline soil in Xinjiang region. In the design, major measures adopted include basement replacement, setting aeolian sand layer and composite geotextile layer, strengthening the subgrade waterproofing and drainage, antiseptic treatment of structures, etc. This paper introduces the subgrade design and construction technology, of which the implementation and application on the test section have achieved a favorable effect and can be taken as the basis for design and construction of similar saline soil subgrade.


2012 ◽  
Vol 510 ◽  
pp. 655-659
Author(s):  
Lie Qu ◽  
Jiu Jun Yang ◽  
Shou Xi Chai ◽  
Lei Guo ◽  
Su Li

The effects of different components, autoclaving temperature and time on the mechanical properties of saline soil bricks were investigated. The autoclaved curing schedule is optimized at autoclaving time of 3h and autoclaving temperature of 175. The optimal material formula consists of water-binding ratio 0.2, CaO 15%, finely grinded quartz powder 20 % and sand 20%, under which the compressive and flexural strengths of saline soil bricks reaches 31.9 Mpa and 7.8Mpa, respectively. Reducing water-binding ratio will effectively promote density, while increasing the amount of CaO will enhance the hydrothermal reaction products, density and the mechanical strength. In addition, adding finely grinded quartz powder and sand will further increase the hydrothermal reaction products and restrict volume shrinkage. Furthermore, elevating autoclaving temperature and extending autoclaving time are favorable to increase density and to improve mechanical properties. But autoclaving time exceeds 3h, the compressive strength will be reduced.


Author(s):  
Н. П. Супрун ◽  
М. Л. Рябчиков ◽  
І. О. Іванов

Create a model for determining the coefficient of friction of textile materials to identify the main factors influencing the process of friction, taking into account the structural and mechanical properties of materials. Modeling of friction process in textile materials as a combination of adhesive and elastic phenomena. Roughness of solid bodies and the main parameters of roughness, such as the height of micro-irregularities, their pitch, sharpening, etc. described in many standards and scientific papers. However, the modeling of the friction process in such systems is very complicated due to the irregularity of distribution of microroughness. The analysis of literature data showed that the surface roughness of textile materials is an important and effective factor in predicting the tactile properties of products for various purposes. Estimation of surface roughness is usually carried out using subjective and objective methods, and the latter can be contact and non-contact. The paper develops a model for determining the coefficient of friction of textile materials to identify the main factors influencing the friction process, taking into account the structural and mechanical properties of materials. Friction force is presented as a combination of two main factors. The first is the elastic resistance to deformation, the second is the adhesive resistance to compression of the structural elements of the material. The main parameters influencing the coefficient of friction of textile fabrics - modulus of elasticity of structural elements, their geometrical parameters - surface density of textile material, linear density of structural elements are established. The obtained results allow to qualitatively predict the friction forces of a textile material with known parameters of its structural elements, as well as to normalize these parameters to create materials with specified friction indices. The obtained results make it possible to select the threads that form the textile material, according to the values of the modulus of elasticity, thickness, location density to ensure the minimum friction force.


2022 ◽  
Vol 12 ◽  
Author(s):  
Ruibo Sun ◽  
Xiaogai Wang ◽  
Yinping Tian ◽  
Kai Guo ◽  
Xiaohui Feng ◽  
...  

Globally soil salinity is one of the most devastating environmental stresses affecting agricultural systems and causes huge economic losses each year. High soil salinity causes osmotic stress, nutritional imbalance and ion toxicity to plants and severely affects crop productivity in farming systems. Freezing saline water irrigation and plastic mulching techniques were successfully developed in our previous study to desalinize costal saline soil. Understanding how microbial communities respond during saline soil amelioration is crucial, given the key roles soil microbes play in ecosystem succession. In the present study, the community composition, diversity, assembly and potential ecological functions of archaea, bacteria and fungi in coastal saline soil under amelioration practices of freezing saline water irrigation, plastic mulching and the combination of freezing saline water irrigation and plastic mulching were assessed through high-throughput sequencing. These amelioration practices decreased archaeal and increased bacterial richness while leaving fungal richness little changed in the surface soil. Functional prediction revealed that the amelioration practices, especially winter irrigation with saline water and film mulched in spring, promoted a community harboring heterotrophic features. β-null deviation analysis illustrated that amelioration practices weakened the deterministic processes in structuring coastal saline soil microbial communities. These results advanced our understanding of the responses of the soil microbiome to amelioration practices and provided useful information for developing microbe-based remediation approaches in coastal saline soils.


2019 ◽  
Vol 9 (17) ◽  
pp. 3537
Author(s):  
Yuexiang Lin ◽  
Limin Peng ◽  
Mingfeng Lei ◽  
Xiang Wang ◽  
Chengyong Cao

Block-in-matrix-rocks (bimrocks) are very complicated geological masses that cause many challenging problems during the design and construction of engineering projects, such as parameter determination and landsliding. Successful engineering design and construction depends on a suitable constitutive model and reliable design parameters for geological masses. In this paper, the vibration attenuation signal of welded bimrocks was obtained and studied using resonance test technology. Combined with a uniaxial compression test, a constitutive model was proposed to describe the mechanical behavior of welded bimrocks. On this basis, the relations between the dynamic elastic modulus and the physical parameters of bimrocks were established, which included macroscopic mechanical parameters and damage constitutive parameters. Consequently, a new technological process was proposed to provide quick identification of the mechanical properties of welded bimrocks. The results indicate that the dynamic elastic modulus is highly correlated with the rock block proportion (RBP) and uniaxial compression strength (UCS). It is an effective parameter to predict the strength of the bimrocks with high RBPs. Additionally, the proposed constitutive model, which is based on damage theory, can accurately simulate the strain softening behavior of the bimrocks. Combining the resonant frequency technology and the proposed constitutive model, the complete stress strain curve can be obtained in a rapid and accurate manner, which provides a further guarantee of the stability and safety of underground engineering.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Linlin Chu ◽  
Yaohu Kang ◽  
Shuqin Wan

Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.


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