Strength and Deformation Characteristics of Stabilized Silty Soil

2012 ◽  
Vol 594-597 ◽  
pp. 512-515
Author(s):  
Zheng Rong Zhao ◽  
Hong Xia Yang

Combined with the silty soil characteristics of the Yellow River alluvial plain and the subgrade filling of Ji-He expressway, the paper discusses silty soil, stabilized silty soil strength and stress-stain characteristics through the indoor triaxial shear test. The results show that the remodeling silty soil has obvious peak, brittle failure, low residual strength after being destroyed and the stress-strain curve shows a softening type in confining pressure 100kPa lower stress level. In the confining pressure 400kPa higher stress level, soil samples peak is not obvious,mainly plastic failure and the stress-strain curve is close to a hardening type. Compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that the partial stress peak is more obvious when destroyed and the residual strength is drastically reduced and more incline to brittle failure. In different the age, compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that internal friction angle becomes larger and cohesion improves gradually whose amplitude is much larger than internal friction angle. Therefore, a more effective way to stabilize the silty soil of the Yellow River alluvial plain is to select silty soil mixed with 4% cement and 4% lime.

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Jianwei Yue ◽  
Limin Zhao ◽  
Baoxi Zhang ◽  
Qingmei Kong ◽  
Siyuan Wang ◽  
...  

The silty clay in the lower reaches of the Yellow River is characterized by loose structure, low strength, and strong capillary effect. Based on the technology of ancient glutinous rice mortar and microbial-induced calcium carbonate precipitation (MICP), experiments on optimal mass ratio of cementitious liquid to bacterial liquid and optimal concentration of cementitious liquid for MICP and improved MICP technology were carried out by measuring the production of CaCO3, and direct shear test and unconfined compressive strength test of plain silt, glutinous mixing silt, and improved silt with MICP and modified MICP were conducted. The microstructure of the reaction products of MICP and improved MICP technology were also evaluated based on scanning electron microscopy (SEM). Research results showed that the mechanical properties of silt with glutinous rice slurry were effectively improved. With the increase in the concentration of glutinous rice slurry, the strength and internal friction angle of soil samples first increased and then decreased, and the cohesion presented a linear increasing trend. When the concentration of cementitious liquid was 0.5 M and the mass ratio of cementitious liquid to bacterial liquid was 2 : 1, the amount of CaCO3 formed was the most, and the conversion rate of Ca2+ was more than 80%. The improved MICP could increase the conversion rate of Ca2+ (93.44%). An improved MICP showed that glutinous rice slurry could improve bacterial activity, increase the urease content in the bacterial solution, and promote the production of CaCO3. Silt cohesion and internal friction angle of the silt were improved by the improved MICP technology, and the strengthening effect of mechanical properties of modified MICP-reinforced soil is better than that of the MICP-reinforced soil; conventional MICP technology could also improve the soil cohesion, but the improvement in the internal friction angle was not obvious. The SEM results indicated that compared with the reaction product of MICP technology, the structure of the product of improved MICP technology is more compact, resulting in a marked reinforcement of MICP performance with glutinous rice slurry. This study provides new insights into enhancing the mechanical behaviour of MICP-treated silt in the Yellow River Basin with glutinous rice slurry.


2018 ◽  
Vol 22 (1) ◽  
pp. 65-71
Author(s):  
Junfu Lu ◽  
Di Li ◽  
Xiaoqiang Xue ◽  
Shenlin Ling

Sandy pebble stratum is a typical discrete particle unstable stratum, mainly consisting of sand and pebble. However, the effect of coarse-grained content on the stability of stratum is not clear. This paper defined the sandy pebble soil of different coarse-grained content in Chengdu City, Sichuan Province, China as the research object. Research on macro-mesomechanical properties of sandy pebble soil of different coarse-grained content was carried out using the method combining the indoor large-scale triaxial test of coarse-grained soil with the discrete element numerical triaxial test. The research results showed that the stress-strain curve of sandy pebble soil exhibited strain softening with the increase of coarse-grained content; when the confining pressure was the same, the stress peak increased and the strain when the peak was reached decreased gradually with the increase of coarse-grained content. It revealed the functional relationship between coarse-grained content and mechanical indexes of sandy pebble soil such as internal friction angle and cohesion. The internal friction angle and cohesion of sandy pebble soil linearly increased with the rise of coarse-grained material; it proposed the particle discrete element micro parameters of sandy pebble soil of different coarse-grained content, including contact modulus, friction coefficient, particle stiffness ratio, contact bond strength. The research results provided the theoretical support for the new design and construction of sandy pebble stratum project. 


Author(s):  
Yueqian Yu ◽  
Guohui Xu ◽  
Xin Wang ◽  
Huixin Liu ◽  
Qingpeng Zhao

Storm waves tend to cause seabed liquefaction by exerting strong cyclic loads on the seabed of the Yellow River Delta. In order to study influences of different wave heights on liquefaction depth of the soil bed, silty soil taken from the Yellow River Delta is used to prepare a soil bed for flume experiments and local parts of superficial soil layer were disturbed by hand. The weakened soil tended to liquefy and slide under wave actions and the liquefaction depth increased with the increasing of wave height. Based on the experimental results, an empirical relationship was proposed between liquefaction depth of silty soil bed and wave height under experimental conditions.


2014 ◽  
Vol 18 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Peiyue Li ◽  
Jianhua Wu ◽  
Hui Qian

<p class="MsoNormal" style="line-height: 200%;">Statistical analyses, a Piper diagram, the saturation index and the correlations of chemical parameters were used to reveal the hydrogeochemistry and hydrogeochemical evolution of shallow groundwater in the southern part of the Zhongwei section of the Yellow River alluvial plain. The water quality for agricultural and domestic uses was also assessed in the study. The results suggest that the shallow groundwater in the study area is fresh to moderately mineralized water. Higher Ca<sup>2+</sup> and HCO<sub>3</sub><sup>-</sup> are observed in the less mineralized water, whereas Na<sup>+</sup> and SO<sub>4</sub><sup>2-</sup> are common ions in the highly mineralized water. The major hydrochemical facies for groundwater with total dissolved solids (TDS) &lt;1 g/L are HCO<sub>3</sub>-Ca·Mg and HCO<sub>3</sub>-Ca·Na·Mg, and for groundwater with TDS &gt; 1 g/L, SO<sub>4</sub>·Cl-Na and SO<sub>4</sub>·Cl-Na·Mg·Ca are the predominant hydrochemical types. The main reactions in the groundwater system are the dissolution/precipitation of gypsum, fluorite, halite, calcite and dolomite. Cation exchange is also important in controlling the groundwater chemistry. The water samples assessed in the paper are of acceptable quality for agricultural use, but most of them are not fit for direct human consumption (drinking). TDS, total hardness (TH), Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> are the main indices that result in the poor drinking water quality.</p><p class="MsoNormal" style="line-height: 200%;"> </p><p class="MsoNormal" style="line-height: 200%;"><strong>Resumen</strong></p><p>Análisis estadísticos, un diagrama de Piper, el índice de saturación y la correlación de los parámetros químicos fueron utilizados para revelar la hidrogeoquímica y la evolución hidrogeoquímica de las aguas subterráneas poco profundas en la parte sur de la sección Zhongwei en la planicie aluvial del río Amarillo. La calidad del agua para el uso doméstico y agrícola también fue evaluada en este estudio. Los resultados sugieren que las aguas subterráneas poco profundas en el área de estudio son entre frescas y moderadamente mineralizadas. Un índice mayor de Ca2+ y HCO3- se observó en las aguas menos mineralizadas, mientras que Na+ y SO42- son iones comunes en las aguas altamente mineralizadas. Los perfiles hidroquímicos predominantes para las aguas subterráneas con Total de Sólidos Disueltos (TDS) &lt;1 g/L son HCO3-Ca·Mg y HCO3-Ca·Na·Mg, y para las aguas subterráneas con TDS &gt;1 g/L, SO4·Cl-Na y SO4·Cl-Na·Mg·Ca. Las mayores reacciones en el sistema de aguas subterráneas son la disolución/ precipitación de yeso, fluorita, halita, calcita y dolomita. El intercambio de cationes también es importante en el control de la química de las aguas subterráneas. Las muestras de agua evaluadas en este manuscrito son de calidad aceptable para el uso agrícola, pero la mayoría no son aptas para el consumo humano. El índice TDS, la dureza total del agua (TH), Cl- y SO42- son las razones principales que influyen en la baja calidad de esta agua.</p>


2016 ◽  
Author(s):  
Zhanyong Yao ◽  
Kai Yao ◽  
Xiaomeng Zhang ◽  
Xiuguang Song ◽  
Teng Ma ◽  
...  

2014 ◽  
Vol 900 ◽  
pp. 445-448
Author(s):  
Zhi Hua Xu ◽  
Da Wei Sun

As the high concrete faced rockfill dams construction, grain breakage gradually become the factors that influence the high dam construction which can not be ignored. This text based on the master of rockfill of shuibuya dam as the experimental material, getting and analyzing the particle breakage data under different confining pressure through the large-scale triaxial test, and the results show that the particle breakage index increases with the increase of confining pressures. The relationship between particle breakage index and confining pressure can be expressed by formula;Particle breakage increase leading to reduced internal friction angle and the shear strength of rockfill, and the author newly introduced two broken variable to describe the relationship which can be expressed by the formula between the particle breakage and internal friction angle, it has certain reference value for establishing constitutive model considering particle breakage.


2011 ◽  
Vol 90-93 ◽  
pp. 260-263
Author(s):  
Hong Xia Yang ◽  
Zheng Rong Zhao

In order to solve the problem of great error in calculating the Yellow River alluvial plain highway’s foundation settlement with delamination summation-method and regulate formula method,we put forward the reason of calculating the final settlement by drilling standard penetration number.It is according to the principles of delamination summation-method and elastic theory method and it is combined with engineering prospecting tests results.Finally,we inference the empirical formula in calculating the final settlement by standard penetration number.The comparison of the calculation of the final settlement by drilling standard penetration number and the statistics by actual observation of jinan-heze expressway has proved the correctness of calculation formula.


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