scholarly journals Numerical Investigation of Slope Stabilization Using Recycled Plastic Pins in Yazoo Clay

2021 ◽  
Vol 6 (3) ◽  
pp. 47
Author(s):  
Mohammad Sadik Khan ◽  
Masoud Nobahar ◽  
John Ivoke

Geographically, at the center of Mississippi is a concentration of High Plastic Yazoo Clay Soil (HPYCS). Shallow landslides frequently occur in embankments constructed with HPYCS caused by rainfall-induced saturation of the embankment slope. The traditional methods are becoming expensive to repair the shallow slope failure. The use of Recycled Plastic Pins (RPPs) to stabilize shallow slope failures offers a significant cost and construction benefit and can be a useful remedial measure for these types of failures. The current study investigates the effectiveness of RPP in slopes constructed with HPYCS, using the Finite Element Method (FEM). The FEM analysis was conducted with the PLAXIS 2D software package. Three uniform and varied RPP spacings were investigated to reinforce 2–4H:1V slopes. Reinforced slope stability analyses were performed to investigate the applicability of RPP in HPYCS. The FEM analysis results indicated that RPP provides shear resistance for the sloping embankment constructed of HPYCS. Uniform spacing of RPP provides sufficient resistance that increases the Factor of Safety (FS) to 1.68 in 2H:1V slopes with deformation of RPP less than 15 mm. The uniform spacing and varied spacing combination of RPP increase the FS to 2.0 with the deformation of RPP less 7 mm.


2021 ◽  
Vol 328 ◽  
pp. 10020
Author(s):  
Ichsan Rauf ◽  
Tri Hrianto ◽  
Kusnadi

This study aims to analyze the deflection behavior of the sheet pile through experimental testing and numerical analysis using the Finite Element Method (FEM). The Laboratorium scale test on a Tub with length of 1500 mm, width of 600 mm, and height of 1500 mm, and Steel Plate 3.2 mm with dimensions of 1400 mm x 590 mm was used as a model of the sheet pile wall. The subgrade material is clay soil and embankment material in the form of Sirtu which passes the No. sieve. 40. Physical and mechanical testing of soil and gravel materials is carried out with reference to ASTM standards. The measurement of the value of the strip load (q) and deflection was carried out using a load cell with a capacity of 100 kN and a linear variable differential transformer (LVDT). The deflection of the sheet pile was using was analyzed using Plaxis 8.2 software of the FEM method. The results of laboratory tests show that the pile wall collapses at a load of 74 kN/m2, with a deflection of 24.56 mm, while the FEM analysis shows that the pile wall collapses at a load of 71 kN/m2 with a deflection of 21.29 mm.



2021 ◽  
Vol 11 (7) ◽  
pp. 3168
Author(s):  
Gioia Fusaro ◽  
Xiang Yu ◽  
Zhenbo Lu ◽  
Fangsen Cui ◽  
Jian Kang

Crucial factors in window performance, such as natural ventilation and noise control, are generally conceived separately, forcing users to choose one over the other. To solve this dualism, this study aimed to develop an acoustic metamaterial (AMM) ergonomic window design to allow noise control without dependence on the natural ventilation duration and vice versa. First, the finite element method (FEM) was used to investigate the noise control performance of the acoustic metawindow (AMW) unit, followed by anechoic chamber testing, which also served as the validation of the FEM models. Furthermore, FEM analysis was used to optimise the acoustic performance and assess the ventilation potential. The numerical and experimental results exhibited an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz. A good agreement between the measured and numerical results was obtained, with a mean variation of 30%. Therefore, the AMW unit optimised acoustic performance, resulting in a higher noise reduction, especially from 50 to 500 Hz. Finally, most of the AMW unit configurations are suitable for natural ventilation, and a dynamic tuned ventilation capacity can be achieved for particular ranges by adjusting the window’s ventilation opening. The proposed designs have potential applications in building acoustics and engineering where natural ventilation and noise mitigation are required to meet regulations simultaneously.



Author(s):  
M. Gotoh ◽  
Y. Shibata

Abstract Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J2-flow theory (J2F), and J2-Gotoh’s corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming processes. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-tube forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square tube reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.



2018 ◽  
Vol 12 (10) ◽  
pp. 3333-3353 ◽  
Author(s):  
Philipp Mamot ◽  
Samuel Weber ◽  
Tanja Schröder ◽  
Michael Krautblatter

Abstract. Instability and failure of high mountain rock slopes have significantly increased since the 1990s coincident with climatic warming and are expected to rise further. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including ice-filled joints. The failure of ice-filled rock joints has only been observed in a small number of experiments, often using concrete as a rock analogue. Here, we present a systematic study of the brittle shear failure of ice and rock–ice interfaces, simulating the accelerating phase of rock slope failure. For this, we performed 141 shearing experiments with rock–ice–rock “sandwich”' samples at constant strain rates (10−3 s−1) provoking ice fracturing, under normal stress conditions ranging from 100 to 800 kPa, representing 4–30 m of rock overburden, and at temperatures from −10 to −0.5 ∘C, typical for recent observed rock slope failures in alpine permafrost. To create close to natural but reproducible conditions, limestone sample surfaces were ground to international rock mechanical standard roughness. Acoustic emission (AE) was successfully applied to describe the fracturing behaviour, anticipating rock–ice failure as all failures are predated by an AE hit increase with peaks immediately prior to failure. We demonstrate that both the warming and unloading (i.e. reduced overburden) of ice-filled rock joints lead to a significant drop in shear resistance. With a temperature increase from −10 to −0.5 ∘C, the shear stress at failure reduces by 64 %–78 % for normal stresses of 100–400 kPa. At a given temperature, the shear resistance of rock–ice interfaces decreases with decreasing normal stress. This can lead to a self-enforced rock slope failure propagation: as soon as a first slab has detached, further slabs become unstable through progressive thermal propagation and possibly even faster by unloading. Here, we introduce a new Mohr–Coulomb failure criterion for ice-filled rock joints that is valid for joint surfaces, which we assume similar for all rock types, and which applies to temperatures from −8 to −0.5 ∘C and normal stresses from 100 to 400 kPa. It contains temperature-dependent friction and cohesion, which decrease by 12 % ∘C−1 and 10 % ∘C−1 respectively due to warming and it applies to temperature and stress conditions of more than 90 % of the recently documented accelerating failure phases in permafrost rock walls.



Author(s):  
Keiji Ogawa ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Kuniyoshi Obata ◽  
Tsukasa Ayuzawa

Microvia formation technology using lasers has become the dominant method for drilling microvia called blind via-holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), drilling directly outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are drilled at the same time, an overhang defect occurs on the drilled hole. However, the overhang generation mechanism has not been clarified. Therefore, we investigated it by detailed observation of the drilled-hole section. Moreover, the overhang length was estimated using the finite element method (FEM). Influences of surface treatment of outer copper foil and thermal properties of the build-up layer were evaluated experimentally and analytically. Consequently, an experiment with a prototype PWB with silica filler added in the build-up layer was carried out. Using the prototype PWBs, the overhang was reduced as shown in FEM analysis results.





2020 ◽  
Vol 14 (2) ◽  
pp. 501-517
Author(s):  
Mohammad Abubakar Naveed ◽  
Zulfiqar Ali ◽  
Abdul Qadir ◽  
Umar Naveed Latif ◽  
Saad Hamid ◽  
...  


2020 ◽  
Vol 14 (1) ◽  
pp. 32-35
Author(s):  
Srđan Medić ◽  
Veljko Kondić ◽  
Tihomir Mihalić ◽  
Vedran Runje

The need for a simple, customised electric vehicle (EV) has inspired the research of the possibility to build a simple EV tailored for the specific needs of the buyer. This paper is focused on the concept of an EV with no conventional control mechanism. In this paper, a research of user needs, vehicle dynamics, vehicle aerodynamics, type of drive and batteries was carried out. EV aerodynamics characteristics were simulated by using the Computational Fluid Dynamics (CFD) software. The control system was designed in correlations with the maximal safe velocity and the radius of EV turning on a circular path. The stability of the EV, concerning the vehicle turning over and wheels slipping while driving in the curves, was the main concern of this paper. The steering wheel and brake pad were replaced with a control stick. Using the Finite Element Method (FEM) analysis, key parts of the construction were constructed.



2011 ◽  
Vol 103 ◽  
pp. 327-331
Author(s):  
Ping Yu Zhu ◽  
Hua Lei ◽  
Yuan Bao Leng

A monitoring structure has been designed to detect settlement using a tube with distributed optical fiber sensors inside. The strain of the optical fibers inside the detecting tube was calculated to estimate the settlement degree of earth dam. The Finite Element Method (FEM) analysis of the tube interaction with the earth dam by ANSYS software is applied to find the best installation location of the detecting tube.



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