scholarly journals Coupling Action of Cooling and Dynamic Load Impact on Deformation Characteristics of High-Salinity Saline Soils

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu Zhang ◽  
Meisi Zou ◽  
Runze Tian ◽  
Anhua Xu ◽  
Yunlong Hou ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Dynamic Load ◽  
Deformation Rate ◽  
Saline Soil ◽  
Time History ◽  
Freezing Temperature ◽  
Soil Samples ◽  
Silty Clay ◽  
Test Results ◽  
Change Rate

In order to grasp the characteristics and mechanism of saline soil deformation under the coupling action of cooling and dynamic load, three types of subgrade fillings from the Qarhan-Golmud Highway in Qinghai-Tibet Plateau were selected as experimental soil samples for the experimental study. Firstly, the freezing temperature experiment was carried out on SS (sandy silt) and HS (high-sulfate silty clay). The test results showed that the freezing temperature of SS is -0.32°C, while that of HC (high-chloride silty clay) and HS will not freeze at -20°C, due to the presence of salt. Secondly, the three soil samples were subjected to deformation characteristic test under coupling action of cooling and dynamic load, respectively, and the time history curve of temperature gradient change, the time history curve of the change rate of deformation, and deformation rate were summarized. Finally, the model of deformation rate vs. time and the model of change rate of deformation vs. deformation rate under the coupling action of cooling and dynamic load are proposed. The test results found that (1) the cooling rate of the temperature gradient curve of the three soil samples showed a rapid cooling rate in the early stage, and it tends to stabilize in the later stage. The distance of the 0°C line from the top gradually decreases, which is affected by the freezing temperature and the salt content. (2) Affected by the freezing temperature and salt type, SS exhibits frost heave, and HS and HC appear to settlement. The final deformation is 1.0%, -0.73%, and -1.10%, respectively. (3) The model of deformation rate vs. time and the model of change rate of deformation vs. deformation rate under the coupling action of cooling and dynamic load were proposed and verified, which are helpful for the evaluation of engineering stability on saline soil subgrade fillings.

scholarly journals Experimental Study of the Space–Time Effect of a Double-Pipe Frozen Curtain Formation with Different Groundwater Velocities

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3830
Author(s):  
Shicheng Sun ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Bin Wang ◽  
Xiaogang Jiang ◽  
...  
Keyword(s):  
Freezing Temperature ◽  
Physical Model Test ◽  
Sand Layer ◽  
Test Results ◽  
Groundwater Velocity ◽  
Test Platform ◽  
The Difference ◽  
Freezing Test ◽  
Double Pipe ◽  
Thermal Physical Properties

Groundwater velocity has significant effects on the formation of a frozen curtain during freezing. In order to study the influence of the velocity on a frozen curtain, a large physical model test platform was established for double-pipe freezing. Based on this platform, freezing tests for different velocities were carried out. Quartz sand was selected as a similar material. The freezing temperature of the saturated sand layer was found by analyzing the results of the nuclear magnetic resonance (NMR). Based on the study of the thermal physical properties of the sand layer, the freezing test results were analyzed, and the results showed that the flow led to the differential development of the temperature between the upstream and downstream sections of the freezing pipes. Moreover, the larger the velocity, the greater the difference. The flow prolonged the overlapping time of the frozen curtains. Additionally, the flow slowed down the development of the frozen curtain area and the frozen curtain thickness. The larger the flow velocity, the greater the inhibition of the flow on the development of the frozen curtain. The test results can provide more references for the design and construction of freezing engineering with flowing groundwater.

Remediation Effect of Biomass Amendment on the Physical-Chemical Performance and Sustainable Utilization of Sandy Soil

2021 ◽  
Vol 45 (1) ◽  
pp. 33-42
Author(s):  
Zibei Ren ◽  
Ming Li ◽  
Yanzhe Hui ◽  
Zengwang Ma ◽  
Jiancai Gu
Keyword(s):  
Sandy Soil ◽  
Saline Soil ◽  
Animal Husbandry ◽  
Soil Improvement ◽  
Sustainable Utilization ◽  
Test Results ◽  
Degraded Soil ◽  
Four Dimensions ◽  
Physical Chemical ◽  
Biological Performance

Soil desertification affects the service functions of the ecosystem. In severe cases, it even causes a decline in agricultural productivity and shrinkage of animal husbandry, posing a threat to regional eco-environment and economic sustainability. The previous research on soil remediation research mainly concentrates on heavy metal degradation, saline soil improvement, and eroded and degraded soil improvement. There is little report on the biomass improvement and restoration of sandy soil. Therefore, this paper explores the remediation effect of biomass amendment on the physical-chemical performance and sustainable utilization of sandy soil in Huangyangtan, the largest sandy land in northern China’s Hebei Province. Specifically, the authors detailed the strategies to measure the physical-chemical indices and microbial diversity of Huangyangtan sandy soil, and introduced the materials and mode of the biomass amendment test on Huangyangtan sandy soil, followed by an elaboration on the test results. The influence of different test fertilizers on the soil was analyzed in four dimensions, namely, physical performance, chemical performance, biological performance, and crop yield. The results show that biomass amendment can effectively remediate sandy soil, and promote its sustainable utilization.

Dynamic Test of Bird Strike on a Flat Plate Made from LY-12 Aluminium

2013 ◽  
Vol 765-767 ◽  
pp. 3158-3161
Author(s):  
Jun Liu ◽  
Zheng Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Dynamic Test ◽  
Time History ◽  
Aircraft Design ◽  
Bird Strike ◽  
Test Results ◽  
Valuable Data ◽  
Good Agreement ◽  
Peak Value

Tests of bird strike have been carried out on plate made from LY-12 Aluminium. The test was down with the projectile impacting the target perpendicularly at velocity of 40m/s, 80m/s, 120m/s respectively. The displacement-time history curves and strain-time history curves of on LY-12 Aluminium plate were measured. The good agreement of the results between two specimens in one group indicated that the results tested in the presnet paper are reliable. The dynamic response of the plate and damage modes of the bird influenced by striking velocity were analyzed. The peak value of the displacement linear enlarged with the increasing of the striking velocity. The test results in the present paper provided valuable data for aircraft design impacted by bird, and also provided abundant test datas for the numerical simulation model applied in bird striking.

scholarly journals Perbandingan Pengujian Konsolidasi Menggunakan Alat Rowe Cell dan Oedometer pada Tanah Lanau Lunak

2020 ◽  
Vol 22 (2) ◽  
pp. 149-155
Author(s):  
Iskandar ◽  
Rabiya
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Samples ◽  
Soil Parameters ◽  
Soil Consolidation ◽  
Test Results ◽  
Soft Soils ◽  
Better Than ◽  
Rowe Cell

Soil consolidation testing using an oedometer and rowe cell. Oedometers are often used on clay and soft soils. However, in the development of the rowe cell device, the results of lowering soft soil were better than the oedometer. The advantage of this rowe cell is that it can determine the saturation value of the soil samples tested. The rowe cell tester can measure the pore water pressure at the beginning and end of each consolidation stage. This rowe cell can provide suitable settlement for soft soils. This consolidation test to obtain soil parameters such as Cv and Cc by using the rowe cell tool. After that, from the test results, the two tools were compared.

Research on the Influences of Broken Ice Parameters on Maneuverable Forces of Ice-Going Ship Oblique Sailing

2021 ◽  
Author(s):  
Shenyu Xuan ◽  
Chengsheng Zhan ◽  
Zuyuan Liu ◽  
Binfeng He ◽  
Qiaosheng Zhao ◽  
...  
Keyword(s):  
Time History ◽  
Test Results ◽  
Ship Maneuvering ◽  
Average Value ◽  
Ocean Science ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Resistance ◽  
Good Agreement

Abstract The broken ice is one of the most common ice conditions for ice-going ships, and the research of ship maneuvering movement in broken ice field can improve sailing safety. In this paper, the discrete element method (DEM) was adopted to study the maneuverable forces, including resistance and transverse force, of ice-going ship oblique sailing in broken ice fields. First, the Araon model tests data of Korea Institute of Ocean Science & Technology (KIOST) was used to verify the ice resistance of direct sailing under different ice sizes and model speeds, and the numerical results are in good agreement with the test results. Second, the influences of broken ice parameters (including concentration, thickness, and shape) on ship-ice interaction and maneuverable forces distribution were researched. The maneuverable forces on the ice-going ships are mainly from the ship-ice interaction. The time history curves of maneuverable forces were analyzed from the average value of maneuverable forces, the average value of peak maneuverable forces, and the number of peaks. Besides, the parameters of broken ice have a heavy influence on the movement of broken ice around the hull, such as accumulating and sliding. The analysis of the broken ice movement contributes to understanding the influences of broken ice parameters on ice-going ships.

scholarly journals Hysteretic Behavior of Steel Reinforced Concrete Columns Based on Damage Analysis

2019 ◽  
Vol 9 (4) ◽  
pp. 687 ◽  
Author(s):  
Bin Wang ◽  
Guang Huo ◽  
Yongfeng Sun ◽  
Shansuo Zheng
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Hysteresis Loops ◽  
Time History ◽  
Hysteretic Behavior ◽  
Loading Path ◽  
Test Results ◽  
Hysteresis Model ◽  
Skeleton Curve ◽  
Steel Reinforced Concrete

With the aim to model the seismic behavior of steel reinforced concrete (SRC) frame columns, in this research, hysteresis and skeleton curves were obtained based on the damage test results of SRC frame columns under low cyclic repeat loading and the hysteretic behavior of the frame columns was further analyzed. Then, the skeleton curve and hysteresis loops were further simplified. The simplified skeleton curve model was obtained through the corresponding feature points obtained by mechanical and regression analysis. The nonlinear combination seismic damage index, which was developed by the test results and can well reflect the effect of the loading path and the number of loading cycle of SRC frame columns, was used to establish the cyclic degradation index. The strength and stiffness degradation rule of the SRC frame columns was analyzed further by considering the effect of the accumulated damage caused by an earthquake. Finally, the hysteresis model of the SRC frame columns was established, and the specific hysteresis rules were given. The validity of the developed hysteresis model was verified by e comparison between the calculated results and the test results. The results showed that the model could describe the hysteresis characteristics of the SRC frame columns under cyclic loading and provide guidance for the elastoplastic time-history analysis of these structures.

Pseudodynamic Test of a Deficient RC Frame Strengthened with Buckling Restrained Braces

2019 ◽  
Vol 35 (3) ◽  
pp. 1163-1187 ◽  
Author(s):  
Ramazan Ozcelik ◽  
Elif Firuze Erdil
Keyword(s):  
Time History ◽  
Shear Capacity ◽  
Test Method ◽  
Nonlinear Time History Analysis ◽  
Rc Frame ◽  
Test Results ◽  
Base Shear ◽  
Braced Frame ◽  
Pseudodynamic Test ◽  
Buckling Restrained Braces

Three story–three bay reinforced concrete (RC) frames with and without chevron braces were tested using the continuous pseudodynamic test method. New steel–concrete composite lateral load–carrying members called Buckling Restrained Braces (BRBs) were used as chevron brace members while retrofitting the RC frame. The BRBs were fitted to the interior span of the RC frame by using anchorage rods. The chevron braced frame was observed to be effective in controlling interstory drift. The test results indicated that retrofitting with BRBs was beneficial in resisting deformation without significant damage under simulated ground motions. Furthermore, significant yielding that occurred on the core plate of the BRBs enabled the braced frame to dissipate energy induced by dynamic loading. The test results were compared with the results of the nonlinear time-history analysis. The analysis results were capable of estimating the base shear capacity and displacement demands with reasonable accuracy.

scholarly journals Undrained Pore Pressure Development on Cohesive Soil in Triaxial Cyclic Loading

2019 ◽  
Vol 9 (18) ◽  
pp. 3821 ◽  
Author(s):  
Andrzej Głuchowski ◽  
Emil Soból ◽  
Alojzy Szymański ◽  
Wojciech Sas
Keyword(s):  
Stress State ◽  
Cyclic Loading ◽  
Pore Pressure ◽  
Cohesive Soil ◽  
Soil Samples ◽  
Test Results ◽  
Soil Behavior ◽  
Pressure Development ◽  
Undrained Conditions ◽  
Excess Pore

Cohesive soils subjected to cyclic loading in undrained conditions respond with pore pressure generation and plastic strain accumulation. The article focus on the pore pressure development of soils tested in isotropic and anisotropic consolidation conditions. Due to the consolidation differences, soil response to cyclic loading is also different. Analysis of the cyclic triaxial test results in terms of pore pressure development produces some indication of the relevant mechanisms at the particulate level. Test results show that the greater susceptibility to accumulate the plastic strain of cohesive soil during cyclic loading is connected with the pore pressure generation pattern. The value of excess pore pressure required to soil sample failure differs as a consequence of different consolidation pressure and anisotropic stress state. Effective stresses and pore pressures are the main factors that govern the soil behavior in undrained conditions. Therefore, the pore pressure generated in the first few cycles plays a key role in the accumulation of plastic strains and constitutes the major amount of excess pore water pressure. Soil samples consolidated in the anisotropic and isotropic stress state behave differently responding differently to cyclic loading. This difference may impact on test results analysis and hence may change the view on soil behavior. The results of tests on isotropically and anisotropically consolidated soil samples are discussed in this paper in order to point out the main features of the cohesive soil behavior.

Research on Methods for Elastic Stiffness of Multi-Ribbed Slab Structure

2010 ◽  
Vol 97-101 ◽  
pp. 1736-1740
Author(s):  
Qi Zhang ◽  
Dong Bo Li ◽  
Qian Feng Yao ◽  
Dong Zhao
Keyword(s):  
Time History ◽  
Elastic Stiffness ◽  
Structural Effect ◽  
Time History Analysis ◽  
Equivalent Model ◽  
Test Results ◽  
History Analysis ◽  
Set Up

Considering the influence of the flange and rib column, the equivalent model of multi-ribbed slab is set up by the theory based on the strengthening isotropism fiber. This model is simple, highly precise and strongly applicable through comparing analyzing results with test results. Besides, the calculated formulate is set up on the basis of the whole structural effect and space work, which offers the prerequisite for elastic time history analysis of the structure.

Contaminant migration in engineered clay barriers due to heat and moisture redistribution under freezing conditions

1995 ◽  
Vol 32 (1) ◽  
pp. 40-59 ◽  
Author(s):  
Abdel M.O. Mohamed ◽  
Raymond N. Yong ◽  
Miroslawa T. Mazus
Keyword(s):  
Temperature Distribution ◽  
Temperature Gradient ◽  
Fluid Intake ◽  
Clay Soil ◽  
Soil Column ◽  
Silty Clay ◽  
Freezing Time ◽  
Contaminant Migration ◽  
Unfrozen Water Content ◽  
Silty Clay Soil

In this study, the effect of temperature distribution and its influence on contaminant migration in a silty clay soil were examined. Three series of freezing-column tests were performed with three different fluids: distilled water, municipal waste leachate, and heavy metal – leachate solution. It was found that temperature distribution as a function of space and time was similar in all tests, most likely as a result of the limited amount of fluid intake. Moisture redistributions were varied as a function of experiment duration and the type of fluid used. The amount of fluid intake was directly related to the freezing time and the temperature gradient in the freezing column. The amount of unfrozen water content, ion concentration and temperature gradient were the controlling parameters that contributed to the contaminant transport in the frozen illitic silty clay soil. Na+-concentration profiles were mostly dependent on water movement in the soil column. The behaviour of Ca2+ and Mg2+ cations was similar to Na+; their concentrations in the soil solution decreased with freezing time due to ion exchange. The large accumulations of Pb2+, Zn2+, Cu2+, and Cd2+ in the lower 10 mm of the soil column occurred as a result of cation exchange and precipitation mechanisms. Key words : unsaturated, osmotic, diffusion, buffer, exchange, transport.

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