Static-dynamic coupling mechanical properties and constitutive model of artificial frozen silty clay under triaxial compression

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To investigate the dynamic splitting tensile mechanical property of limestone under coupled static and dynamic state, the dynamic split tensile tests of limestone under one-dimensional coupled static and dynamic load with different strain rates were performed with the help of modified split Hopkinson pressure bar (SHPB) equipment. The dynamic splitting tensile mechanical property and energy dissipation characteristic under two stress states were also compared in this research. Test results indicated that the dynamic tensile strength of the limestone specimen increased with the increase of average strain rate, exhibiting an obvious strain rate effect. In addition, dynamic tensile strength under uniaxial state was higher than that under one-dimensional coupled static and dynamic load state under the same test condition. Moreover, the deformation modulus increased with increasing average strain rate under uniaxial state, while it decreased with increasing average strain rate under coupled static and dynamic state. Both the reflected energy and absorbed energy linearly increased with increasing incident energy. The preload in the radial direction could increase the reflected energy and decrease the absorbed energy. Moreover, the transmitted energy with preload state was slightly lower than that under uniaxial state. Finally, the dynamic tensile strength of limestone specimen increased as a power function with increasing absorbed energy.

Section: Energy Dissipation Analysis Of Limestonementioning

confidence: 99%

Coupled Static-Dynamic Tensile Mechanical Properties and Energy Dissipation Characteristic of Limestone Specimen in SHPB Tests

Ping

Fang

et al. 2020

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“…e computerized data acquisition system continuously recorded the three-wave signals generated during impact. Based on elastic stress wave theory and uniform stress assumption, the dynamic compressive strength (σ s ) and dynamic tensile strength (σ t ) could be calculated [23,24] as follows:…”

Section: Dynamic Compressive Test and Dynamic Tensile Testmentioning

confidence: 99%

Effect of Basalt Fiber on Static and Dynamic Mechanical Properties of Metakaolin-Based Cement Clay

Huang

2020

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To investigate the effects of basalt fiber content on the mechanical properties and microstructure characteristic of metakaolin-based cement clay, the static and dynamic uniaxial compressive and splitting tensile, nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) tests were performed to study the stress-strain curves, static and dynamic peak stress, pore distribution characteristic, and reinforcement mechanism. In this research, the basalt fiber with the length of 12 mm were selected and the ratios between fiber and dry soil were 0%, 0.5%, 1.0%, 1.5%, and 2.0%, respectively. The obtained results showed a noticeable difference of stress-strain curve characteristics in the static and dynamic compressive tests. A positive correlation between deformation modulus and compressive strength was found for both static and dynamic tests. The addition of basalt fiber could efficiently increase the static and dynamic strengths of metakaolin-based cement clay, and the increment 66.15% and 74.63% was observed at 1.0% basalt fiber content for static and dynamic compressive strengths, respectively, while the corresponding increment values were 93.75% and 97.62% for its splitting tensile strengths, respectively. The basalt fiber could decrease the porosity of cement clay; moreover, the reinforcement mechanism of metakaolin and basalt fiber to cement clay was analyzed based on the SEM test results.

“…e water content of frozen silty soil in this study was 24.2%. Each specimen prepared for static and dynamic loading had dimensions of V 50 mm × 100 mm and V 50 mm × 50 mm [6], respectively. e soil was prepared with different binders (i.e., gypsum, Vaseline, and no binder) with one prefabricated crack; after determining the suitable binder materials, we prepared frozen silty soil specimens with different number of prefabricated cracks at an angle of zero degrees; taking dynamic specimen as an example, the prefabricated crack production method was as follows: a half specimen (V 50 mm × 25 mm) and a quarter specimen (V 50 mm × 12.5 mm) were made using suitable corresponding moulds, and then two half specimens were placed together to make specimen with one prefabricated crack, while one half specimen and two quarter specimens were used for preparing specimen with two prefabricated cracks, and four quarter specimens were used for specimen with three prefabricated cracks.…”

Section: Preparation Of Frozen Soil With Prefabricatedmentioning

confidence: 99%

“…e mechanical properties of frozen soil were more complex compared to ordinary soil due to the ice particles, which showed high sensitivity to temperature change in surrounding environment [4,5]. Seasonal frozen soil covered about 53.5% of China's land area [6]. Quick development rate in the fields of technology and engineering in previous years led to a gradual increase in the number of construction projects in cold regions, such as tunnels, highways, pipelines, and railways [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Effects of Prefabricated Crack and Strain Rate on Uniaxial Compressive Properties of Frozen Silty Soil

Kaunda

Huang

2020

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To investigate the uniaxial compressive strength and deformation properties of frozen silty soil with prefabricated crack under various strain rates, the static uniaxial compressive tests were conducted for frozen silty soil using three kinds of binder materials to select the suitable prefabricated crack manufacturing method. Afterward, the static and dynamic stress-strain curves of frozen silty soil with different prefabricated crack numbers were obtained based on static and splitting Hopkinson pressure bar (SHPB) tests. In addition, the high-speed camera was employed to record the fracturing process of frozen silty soil under impact loads. Results indicated that the frozen silty soil specimens with no binder showed higher static strength compared with other two binder materials (plaster and Vaseline). The strength growth rate of frozen silty soil showed three-stage (fast-slow-rapid) change characteristics. The peak strain of frozen silty soil under static loads scope was higher compared with that under dynamic loads, while its dynamic peak strain with various prefabricated crack numbers was remarkably rate-dependent. The absorbed energy density of frozen silty soil was subject to a negative (positive) relationship with the prefabricated crack numbers (strain rate). The dominated crack of intact frozen silty soil specimen finally presented Y-shaped shear failure. However, tensile cracks parallel to stress wave propagation direction were observed for the frozen silty soil specimen with prefabricated crack.