scholarly journals Experimental Study on Mechanical Properties of Reinforced Soil Interface under Dry-Wet Cycle

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Liang Huang ◽  
Wenbo Ma ◽  
Yujie Hou ◽  
Bo Wang ◽  
Jiahua Zhu
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Working Conditions ◽  
Retaining Wall ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Overburden Pressure ◽  
Pull Out ◽  
Apparent Cohesion ◽  
Soil Interface

The reinforced soil-retaining wall has been widely used in coastal projects, and the dry-wet cycles influence the mechanical properties of the reinforced soil interface. This study conducts macro-micro tests and selects four different water content samples of reinforced soil with five types of overburden pressure conditions and three sets of dry-wet cycles, with a total of 60 working conditions. The pull-out test was used to study the mechanical properties of the reinforced soil interface. The scanning electron microscope was used to observe the microscopic characterization of the particles under different working conditions. Through the analysis of the experimental results, we can draw the conclusion as follows. (1) The friction coefficient of the reinforced soil interface decreases with the increase of the number of dry and wet cycles. (2) The apparent cohesion of soil-reinforcement interface decreases with the increase of the number of dry-wet cycles. After 30 dry-wet cycles, the apparent cohesion of the soil-reinforcement interface with water content of 14% is the maximum 5.91 kPa. The variation law of cohesion derived from microstructure analysis conforms to the laws and conclusions obtained by the experiment. (3) The shear stress of the reinforced soil is linearly related to the normal stress, which is in accordance with Coulomb’s law.

scholarly journals Microstructure and Macromechanical Properties of Retaining Structure of Near-Water Reinforced Soil under Dry-Wet Cycle

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Yujie Hou ◽  
Bo Wang ◽  
Liang Huang ◽  
Jianguo Xu ◽  
Dun Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Surface ◽  
Reinforced Soil ◽  
Overburden Pressure ◽  
Soil Particles ◽  
Retaining Structure ◽  
Pull Out ◽  
Long Time ◽  
Reinforced Materials

Reinforced soil-retaining structures that have been working in near-water environments for a long time are likely to affect their own mechanical properties due to the dry-wet cycle caused by changes in water level. In response to this problem, this paper uses a combination of macro- and microtests, selecting reinforced soil samples with four water content conditions, five overburden pressure conditions, three sets of dry-wet cycle conditions, and a total of 60 working conditions for testing. Scanning electron microscopy was used to observe the microscopic characterization of the reinforced soil particles under different times of the dry-wet cycle, and the pull-out test was used to study the mechanical properties of the interface of the reinforced materials and soils. The analysis results of the test show that the dry-wet cycles increase the porosity of the reinforced soil and the number of pores, among which the proportion of micro and small pores increases, the abundance and fractal dimension of reinforced soil particles increase, and the roughness of the particle surface is reduced. The change of the microstructure of the reinforced soil causes the cohesion of the soil to decrease in the macroscopic view. The friction coefficient and the ultimate pull-out force of the interface between the reinforced materials and the soils decrease with the increase of times of dry-wet cycle.

scholarly journals Model Test of the Reinforcement of Surface Soil by Plant Roots under the Influence of Precipitation

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hengxing Wang ◽  
Yulong He ◽  
Zufeng Shang ◽  
Chunpeng Han ◽  
Yilu Wang
Keyword(s):  
Water Content ◽  
Model Test ◽  
Surface Soil ◽  
Plant Root ◽  
Root Systems ◽  
Reinforced Soil ◽  
Plant Roots ◽  
Interfacial Friction ◽  
Negative Power ◽  
Pull Out

We present the results of the reinforcement of plant root systems in surface soil in a model test to simulate actual precipitation conditions. In the test, Eleusine indica was selected as herbage to reinforce the soil. Based on the various moisture contents of plant roots in a pull-out test, a fitting formula describing the interfacial friction strength between the roots and soil and soil moisture content was obtained to explain the amount of slippage of the side slope during the process of rainfall. The experimental results showed that the root systems of plants successfully reinforced soil and stabilized the water content in the surface soil of a slope and that the occurrence time of landslides was delayed significantly in the grass-planting slope model. After the simulated rainfall started, the reinforcement effect of the plant roots changed. As the rainfall increased, the interfacial friction between the roots and the soil exhibited a negative power function relationship with the water content. These conclusions can be used as a reference for the design of plant slope protection and reinforcement.

Quantification of mechanical and hydric components of soil reinforcement by plant roots

2015 ◽  
Vol 52 (11) ◽  
pp. 1839-1849 ◽  
Author(s):  
G. Veylon ◽  
M. Ghestem ◽  
A. Stokes ◽  
A. Bernard
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Failure Modes ◽  
Friction Angle ◽  
Soil Reinforcement ◽  
Plant Roots ◽  
Mechanical Reinforcement ◽  
Mechanical Component ◽  
Apparent Cohesion

The use of vegetation to stabilize slopes with regard to shallow landslides is an ecological and economic alternative to traditional solutions of civil engineering. This study aims at quantifying the effect of soil water content on the reinforcement of soil by plant roots and determines how soil water content influences the failure modes of roots during shear. Direct shear box tests were performed on three species used in hillslope reforestation programs in Yunnan, China. Reinforcement was quantified and divided into a hydric component corresponding to the effect of water removal and a mechanical component reflecting the influence of roots on apparent cohesion and friction angle. It was shown that the hydric component of reinforcement can be of the same order as the mechanical component and that root system architectural traits influence the type of mechanical reinforcement (cohesive or frictional). We also demonstrate the potential development of matric suction effects on the shear strength of soil.

In-situ pull-out tests on soil-reinforcement interface properties of reinforced soil slopes

2018 ◽  
Vol 42 (1) ◽  
pp. 41-56
Author(s):  
CUNJIA QIU QIU ◽  
SHUANG WANG ◽  
HONG LIU ◽  
Jin HUANG
Keyword(s):  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Interface Properties ◽  
Pull Out ◽  
Soil Slopes

scholarly journals Contribution of suction on the stability of reinforced-soil retaining wall

2018 ◽  
Vol 195 ◽  
pp. 03004
Author(s):  
Nurly Gofar ◽  
Hanafiah
Keyword(s):  
Stability Analysis ◽  
Retaining Wall ◽  
Design Guidelines ◽  
Reinforced Soil ◽  
Cohesionless Soil ◽  
Numerical Studies ◽  
Local Soil ◽  
Apparent Cohesion ◽  
The Stability ◽  
Unsaturated Condition

Existing design methods of a reinforced-soil retaining wall were established for walls with cohesionless soil backfill. However, local soil has been used widely in the construction of such a wall for economic reasons. Laboratory and numerical studies have pointed out the merit of using cohesive backfill in association with geosynthetic reinforcement. Since the compacted soil was in an unsaturated condition during the construction of the reinforced wall, the apparent cohesion derived from both soil mineralogy and suction could contribute to the stability of the wall. This paper considers methods to include the suction contribution to the existing design guidelines based on slope stability analysis, i.e. simplified method and simplified stiffness method. The analyses were carried out on a case study of geosynthetics reinforced soil retaining wall. Results show that the contribution of suction as part of cohesion existing in the cohesive backfill could be considered for the stability analysis of reinforced soil retaining walls using the available design guidelines.

An experimental investigation into the behavior of sand reinforced by tubular braided structures

2019 ◽  
pp. 152808371986694 ◽  
Author(s):  
Makan Noorbakhsh ◽  
Mohamadali Rowshanzamir ◽  
Sayyed Mahdi Abtahi ◽  
Sayyed Mahdi Hejazi
Keyword(s):  
Areal Density ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Direct Shear Tests ◽  
Pull Out ◽  
Standard Plate ◽  
Similar Materials ◽  
Interaction Element ◽  
Load Tests ◽  
Braided Structure

This study introduces the tubular braided structure as a new geosynthetic material for sand reinforcement. The performance of a tubular braid under the influence of similar soil–reinforcement interaction mechanisms has been investigated to emphasize the effect of the reinforcement form on the performance of the reinforced soil composite. For this purpose, three series of interaction element tests including direct shear tests, pull-out tests, and soil stress control tests were conducted on the unreinforced and reinforced sand. Finally, the overall performance of the reinforced foundation bed with the planar and tubular reinforcing textile (with similar materials, properties, texture, and areal density) was evaluated through a series of standard plate load tests. The results indicated that the performance of the sand-braid composite was better compared to the similar typical planar reinforcement, except for the case of pull-out test. Tubular braid resulted in the enhanced shear strength of the reinforced soil composites, mobilization of the excess compressive stress in the enclosed soil inside the tubular braids, reduction in the vertical stress level of the footing model transferred down through the soil bed, the increase of the average bearing capacity of the footing model, and a significant reduction in the footing settlement.

scholarly journals Pull-Out Resistance of Sand-Geosynthetics Reinforcement

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
M. K. A. Ismail ◽  
◽  
M. I. Joohari ◽  
A. Habulat ◽  
F. A. Azizan ◽  
...  
Keyword(s):  
Retaining Wall ◽  
Normal Pressure ◽  
Soil Reinforcement ◽  
Silica Sand ◽  
Laboratory Model ◽  
Site Location ◽  
Retaining Structures ◽  
Reinforcement Mechanism ◽  
Pull Out ◽  
Earth Retaining Structures

Geosynthetics are widely used in earth retaining structures such as steep slope and earth retaining wall. The stability of the earth retaining structures depends on the interaction between geosynthetics and soil at the reinforced area known as reinforcement mechanism. The reinforcement mechanism of the soil reinforced structure usually difficult to be analysed thoroughly. It is because the preliminary study on the pull-out resistance and durability of the reinforcement material is not taking into account before it has been used to the site location especially in Malaysian practises. Less supervision and the assessment after the installation of the reinforcement materials also contributed to the failure of the soil reinforcement. In this paper, the laboratory model was used to imply the real condition of the soil reinforced structure using pull-out test. A standard pull-out test was carried out by using geotextile and geogrid reinforcing elements embedded into silica sand of size D50=1.357 mm and D50=0.571 mm subjected to normal pressures of 100 kPa, 150 kPa and 200 kPa. Comparative result and analysis showed that the geotextile reinforcement give more resistance rather than geogrid reinforcement under high normal pressure.

scholarly journals The Influence of Water Content on the Settlement Behaviour of Polypropylene Fibre-Reinforced Dredged Marine Soil (DMS)

2019 ◽  
Vol 7 (4.14) ◽  
pp. 434
Author(s):  
M. Z. Rosman ◽  
C-M. Chan
Keyword(s):  
Water Content ◽  
Land Reclamation ◽  
Glass Fibers ◽  
Construction Materials ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
High Water Content ◽  
Chemical Additives ◽  
Conventional Concrete ◽  
Marine Soil

The use of fiber as soil reinforcement is not new in civil engineering field. In the earlier times, rice straw was mixed together with mud or clay to produce construction materials such as brick and concrete. Conventional concrete mix without fiber tends to exhibit brittleness behaviour. Hence, there is a growing attention on using current reinforcement materials such as steel, polypropylene and glass fibers. It is reported that fiber in concrete provide bridging effect, which transfer and distribute load evenly, thus increasing ductility. Now, similar concept of fiber inclusion in concrete can be applied to the case of problematic soil. The addition of chemical additives such as cement in soil resulted with stiffness and brittleness. As solution, numerous studies have shown that the fiber inclusion in soil have increased strength, permeability and ductility. Due to the many studies of fibre-reinforced soil related to its shear strength, the present study will investigate the compressibility behaviour of the fibre-reinforced soil through oedometer test. In this study, the dredged marine soil (DMS) was mixed together with 0.25, 0.5, 0.75 and 1 % of polypropylene (PP) fiber. Two conditions of soil, namely high water content (1.40LL) and low water content (0.90LL) were tested. Samples with 0.90LL water content show great reduction of settlement than samples with 1.40LL water content. The outcome of this study will suggest the beneficial reuse of DMS for engineering application such as backfill material, land reclamation or clay liner for landfills.  

scholarly journals The Mechanical Property of Bidirectional Geogrid and its Application Research in Retaining Wall Design

2015 ◽  
Vol 9 (1) ◽  
pp. 214-222 ◽  
Author(s):  
Wang Qingbiao ◽  
Zhang Cong ◽  
Wang Tiantian ◽  
Bai Yun ◽  
LÜ Rongshan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Retaining Wall ◽  
Strain Curve ◽  
Social Benefit ◽  
Reinforced Soil ◽  
Design Calculation ◽  
Affecting Factors ◽  
Soil Pressure ◽  
Factors Affecting

The introduction and rise of new geotechnical composite material greatly promote the development of civil engineering construction. Studying the mechanical properties of bidirectional geogrid and determining the reinforced soil retaining wall design calculation based on the friction reinforcement theory provide theoretical basis and research foundation for its application in the practical engineering. The mechanical properties of bidirectional geogrid are analyzed in depth through theoretical analysis, experimental research and numerical simulation. The mechanical property tests in light of different affecting factors are studied and the application of geogrid material in the reinforced soil retaining wall is simulated, thus yielding the conclusions as follows: (1) Study the mechanical properties in different temperature, loading and packing with the help of indoor pullout test and analyze the main factors affecting the mechanical properties of the geogrids in theory. (2) Analyze the reinforced soil retaining wall with friction reinforcement principle. Determine the calculation method of soil pressure and reinforcement and the check formula of the overall stability of the whole wall design and calculate the geogrid reinforced soil retaining wall in theory. (3) Simulate the bidirectional geogrid reinforced soil retaining wall with FLAC3D and analyze the force of the retaining wall. Study the stress-strain curve according to the parameters of reinforced geogrid and retaining wall and analyze the overall force to guide the safety of the site construction. (4) Apply to the reinforced soil the retaining wall design. Thus the result is achieved that bidirectional geogrid is simple in construction, excellent in performance and economic in cost and has a good application prospect and social benefit.

Sign in / Sign up

Export Citation Format

Share Document