scholarly journals Analysis of the Working Performance of a Back-to-Back Geosynthetic-Reinforced Soil Wall

2022 ◽  
Vol 12 (1) ◽  
pp. 516
Author(s):  
Guangqing Yang ◽  
Yunfei Zhao ◽  
He Wang ◽  
Zhijie Wang
Keyword(s):  
Design Method ◽  
Fem Analysis ◽  
Tensile Tests ◽  
Design Guidelines ◽  
Reinforced Soil ◽  
Superior Performance ◽  
Geosynthetic Reinforced Soil ◽  
Working Performance ◽  
Materials Used ◽  
Two Parameters

Back-to-back geosynthetic-reinforced soil walls (BBGRSWs) are commonly used in embankments approaching bridges and narrow spaces. However, the available literature and design guidelines for BBGRSWs are limited. The aims of this research were to develop a greater understanding of the working performance of BBGRSWs and to optimize the design method of a BBGRSW to ensure the cost-efficiency as well as the stability of the structure. On the basis of a monitored BBGRSW structure located in China, we established a numerical model. The parameters of the materials used in the actual project were determined through triaxial and tensile tests. The numerical results were compared with the measured results in the field to verify the correctness of the selected parameters. Two parameters were investigated by the FEM method: the reinforcement length and the arrangement. The FEM analysis indicated that post-construction deformations such as displacement and settlement could be reduced by reinforcing the same layer on both sides. Longer reinforcements were needed to achieve the same performance if the reinforcements were cross-arranged. Thus, BBGRSWs can have a superior performance if the reinforcements are connected in the middle from both sides. Even with longer reinforcements, the safety factor of the wall with a cross-arranged reinforcement was smaller than that with same-layered reinforcements.

FEM Analysis on Tensile Force of Geosynthetic Reinforcement Arranged in GRS-RW Considering Variable Loading Rate

2012 ◽  
Vol 188 ◽  
pp. 60-65
Author(s):  
Fu Lin Li ◽  
Fang Le Peng
Keyword(s):  
Finite Element ◽  
Loading Rate ◽  
Retaining Wall ◽  
Tensile Force ◽  
Fem Analysis ◽  
Reinforced Soil ◽  
Geosynthetic Reinforcement ◽  
Geosynthetic Reinforced Soil ◽  
Rate Dependent ◽  
Dependent Behavior

The combined effects of the rate-dependent behavior of both the backfill soil and the geosynthetic reinforcement have been investigated, which should be attributed to the viscous property of material. A nonlinear finite element method (FEM) analysis procedure based on the Dynamic Relaxation method was developed for the geosynthetic-reinforced soil retaining wall (GRS-RW). In the numerical analysis, both the viscous properties of the backfill and the reinforcement were considered through the unified nonlinear three-component elastic-viscoplastic model. The FEM procedure was validated against a physical model test on geosynthetic-reinforced soil retaining wall with granular backfill. Extensive finite-element analyses were carried out to investigate the tensile force distributions in geosynthetic reinforcement of geosynthetic-reinforced soil retaining wall under the change of loading rate. It is found from the analyses that the presented FEM can well simulate the rate-dependent behavior of geosynthetic-reinforced soil retaining wall and the tensile force of geosynthetic reinforcement arranged in retaining wall.

Strain-softening model evaluating geobelt–clay interaction validated by laboratory tests of sensor-enabled geobelts

2020 ◽  
Vol 57 (3) ◽  
pp. 354-365 ◽  
Author(s):  
Xin-zhuang Cui ◽  
Yi-lin Wang ◽  
Kai-Wen Liu ◽  
Jun Li ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Strain Softening ◽  
Tensile Tests ◽  
Reinforced Soil ◽  
Uniaxial Tensile ◽  
Hyperbolic Model ◽  
Direct Shear ◽  
Direct Shear Tests ◽  
Geosynthetic Reinforced Soil ◽  
Pull Out ◽  
Pullout Tests

The interaction between geosynthetics and soil is vital for the stability and the bearing capacity of geosynthetic-reinforced soil structures. This contact behavior between geosynthetics and granular soils has been extensively studied in the literature while there is scarcity of it related to geosynthetics and cohesive soils particularly with softening responses. This paper presents a strain-softening model of geobelt–clay interaction based on direct shear test results under two compaction degrees. A theoretical model for evaluating the pullout behavior of a geobelt is proposed by employing the strain-softening model verified by direct shear tests and a hyperbolic model capturing the stress–strain curves of a geobelt calibrated by uniaxial tensile tests. The proposed model is numerically solved and validated by pullout tests. A kind of sensor-enabled geobelt (SEGB) was adopted in all the aforementioned tests. Both test and numerical results show an overall softening trend in terms of front pull-out force versus displacement. Generally, the model proposed can give reasonably good agreement between calculations and test data during the whole pull-out range. Also, the strain distributions measured by SEGBs demonstrate the working process during the pullout tests, which makes SEGBs a potentially new choice for the strain measurements of in-soil geobelts.

scholarly journals A New Extension of Thinning-Based Integer-Valued Autoregressive Models for Count Data

Entropy ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 62
Author(s):  
Zhengwei Liu ◽  
Fukang Zhu
Keyword(s):  
Likelihood Estimation ◽  
Real Data ◽  
Autoregressive Models ◽  
Superior Performance ◽  
Data Sets ◽  
Binomial Thinning ◽  
Free Case ◽  
Two Parameters ◽  
Conditional Maximum ◽  
Thinning Operator

The thinning operators play an important role in the analysis of integer-valued autoregressive models, and the most widely used is the binomial thinning. Inspired by the theory about extended Pascal triangles, a new thinning operator named extended binomial is introduced, which is a general case of the binomial thinning. Compared to the binomial thinning operator, the extended binomial thinning operator has two parameters and is more flexible in modeling. Based on the proposed operator, a new integer-valued autoregressive model is introduced, which can accurately and flexibly capture the dispersed features of counting time series. Two-step conditional least squares (CLS) estimation is investigated for the innovation-free case and the conditional maximum likelihood estimation is also discussed. We have also obtained the asymptotic property of the two-step CLS estimator. Finally, three overdispersed or underdispersed real data sets are considered to illustrate a superior performance of the proposed model.

scholarly journals Mechanical Optimization of Concrete with Recycled PET Fibres Based on a Statistical-Experimental Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 240
Author(s):  
Alejandro Meza ◽  
Pablo Pujadas ◽  
Laura Montserrat Meza ◽  
Francesc Pardo-Bosch ◽  
Rubén D. López-Carreño
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Superior Performance ◽  
Fibre Reinforced Concrete ◽  
Marine Fauna ◽  
Recycled Pet ◽  
Pet Bottles ◽  
Fibre Aspect Ratio

Discarded polyethylene terephthalate (PET) bottles have damaged our ecosystem. Problems of marine fauna conservation and land fertility have been related to the disposal of these materials. Recycled fibre is an opportunity to reduce the levels of waste in the world and increase the mechanical performance of the concrete. PET as concrete reinforcement has demonstrated ductility and post-cracking strength. However, its performance could be optimized. This study considers a statistical-experimental analysis to evaluate recycled PET fibre reinforced concrete with various fibre dose and aspect ratio. 120 samples were experimented under workability, compressive, flexural, and splitting tensile tests. The results pointed out that the fibre dose has more influence on the responses than its fibre aspect ratio, with statistical relation on the tensional toughness, equivalent flexural strength ratio, volumetric weight, and the number of fibres. Moreover, the fibre aspect ratio has a statistical impact on the tensional toughness. In general, the data indicates that the optimal recycled PET fibre reinforced concrete generates a superior performance than control samples, with an improvement similar to those reinforced with virgin fibres.

Comparison of Field Behavior with Results from Numerical Analysis of a Geosynthetic Reinforced Soil Integrated Bridge System Subjected to Thermal Effects

2020 ◽  
Vol 2674 (1) ◽  
pp. 294-306
Author(s):  
Arshia Taeb ◽  
Phillip S.K. Ooi
Keyword(s):  
Pressure Fluctuations ◽  
Axial Loading ◽  
Reinforced Soil ◽  
Element Analysis ◽  
Vertical Pressure ◽  
Geosynthetic Reinforced Soil ◽  
End Wall ◽  
Cyclic Straining ◽  
Toe Pressure ◽  
Bridge System

When subjected to ambient daily temperature fluctuations, a 109.5 ft-long geosynthetic reinforced soil integrated bridge system (GRS-IBS) was observed to undergo cyclic straining of the superstructure. The upper and lower reaches of the superstructure experienced the highest and lowest strain fluctuation, respectively. These non-uniform strains impose not only axial loading of the superstructure but also bending. Pure axial loading in a horizontal superstructure will cause the footings to slide. However, bending in the superstructure will cause the footings to rotate thereby inducing cyclic fluctuations of the vertical pressure beneath the footing and also lateral pressure behind the end walls. Measured vertical footing pressure closest to the stream experienced the greatest daily pressure fluctuation (≈ 2,500–3,000 psf), while that nearest the end wall experienced the least. The toe pressure fluctuations seem rather large. That these large vertical pressure fluctuations are observed in a tropical climate like Hawaii when no other GRS-IBS in temperate regions has reported the same (or perhaps higher fluctuation) is indeed surprising. The larger these pressures are, the greater the likelihood of inducing cyclic-induced deformations of the GRS abutment. A finite element analysis of the same GRS-IBS was performed by applying an equivalent temperature and gradient to the superstructure over the coldest and hottest periods of a day to see if the field measured values of pressures are reasonable and verifiable, which indeed they were. This methodology is novel in the sense that the effects of axial load and bending of the superstructure are simulated using measured strains rather than measured temperatures.

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