scholarly journals Study on the effect of some parameters of soil nails on the stability of vertical slopes

2020 ◽  
Vol 61 (6) ◽  
pp. 30-37
Author(s):  
Nhan Thi Pham ◽  
Pan Bing ◽  
Nghia Viet Nguyen ◽  
Keyword(s):  
Soil Reinforcement ◽  
Viet Nam ◽  
Soil Nailing ◽  
Soil Nails ◽  
Soil Nail ◽  
Concrete Piles ◽  
Hydropower Plants ◽  
Reinforced Concrete Piles ◽  
The Stability ◽  
Inclined Angle

Soil nailing is one of the soil reinforcement techniques that has been used worldwide in geotechnical engineering. In Viet Nam, soil nailing technology applied in a number of transportation investments such as Ha Long - Van Don, Bac Giang - Lang Son highways, and some of the hydropower plants in the central provinces of Viet Nam. Soil nailing is a system consisting of reinforced concrete piles and rebars or composite rods installed in an inclined direction into the slope. The research and applications of soil nailing technology to reinforceslopes in Viet Nam have not been widespread. The authors only considered construction technologies, processes, requirements for the materials, equipment, quality - check of soil nails, etc. The optimal geometries of soil nails for the stability of slope are inadequate and analyzed thoroughly. These lead to inaccurate prediction of the construction stabilization effect and the safety of designed structures. In the present study, numerical simulations were conducted to investigate the effects of the inclined angle and the length of soil nail Patterns and subjected to surcharge loads on stability improvement of soil - nailed slopes and facing deformation in a staged - excavation. The research results show that the soil nail reinforcement efficiency could be affected by inclinations and length Pattern s of soil nails. The general conclusion is that the more soil is nailing inclinations, the more the reinforcing forces in the soil nails. The soil nail length Patterns have also influenced displacement characteristics of slopes.

Influence of Soil Dilatancy on Soil Nail Pull-Out Resistance in Completely Decomposed Granite Fill

2007 ◽  
Vol 340-341 ◽  
pp. 1237-1242
Author(s):  
Li Jun Su ◽  
Jian Hua Yin ◽  
Hong Jian Liao
Keyword(s):  
Field Tests ◽  
Soil Mass ◽  
Soil Nails ◽  
Soil Nail ◽  
Pull Out ◽  
Parametric Studies ◽  
Decomposed Granite ◽  
The Stability ◽  
Completely Decomposed Granite ◽  
Soil Dilatancy

Soil nailing, developed from the New Austrian Tunnelling Method, has been widely used in many countries and regions in the world since the 1970’s. This technique is used to stabilize in situ soil mass by installing a large number of closely spaced unstressed inclusions into the soil mass to increase its strength and stability. Since the mid 1970’s, several design methods have been proposed based on laboratory and field tests. Among the design criteria in these methods, the pull-out resistance of a soil nail is a key parameter that controls the stability assessment of soil nail structure. In the previous investigations, the soil dilatancy was found to be an important factor that influences the soil nail pull-out resistance especially for drill-and-grout soil nails. In order to study the influence of soil dilatancy on soil nail pull-out resistance, laboratory pull-out tests and numerical parametric studies have been carried out for soil nails in Completely Decomposed Granite (CDG) fill. The results show that the soil dilatancy has a significant influence on the soil nail pull-out resistance.

The Analys of Stability of Composite Soil Nail

2014 ◽  
Vol 580-583 ◽  
pp. 503-508 ◽  
Author(s):  
Yong Zeng
Keyword(s):  
New Technology ◽  
Practical Significance ◽  
Soil Nailing ◽  
Local Conditions ◽  
Soil Nail ◽  
Composite Soil Nailing ◽  
The Stability ◽  
The Right ◽  
Organic Combination ◽  
Stability Of Structure

Composite soil nailing technology is a new technology which developed on the basis of the soil nailing supporting technology. This new technology has a very important practical significance to the construction, for which the scale is larger and larger, the condition is more and more complex and the excavation of foundation is more and more deep. Composite soil nailing technique is mainly introduced in this paper by its main form of structure and the main principle, which draw a conclusion that different forms of the combination of support types have different effects on the stability of structure, by analyzing the support stability. This thesis shows that we should adjust measures to local conditions, choose the right organic combination. At the same time it also provides the basis for the practical application of engineering support.

scholarly journals Numerical Investigation of a Foundation Pit Supported by a Composite Soil Nailing Structure

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 252 ◽  
Author(s):  
Wei Han ◽  
Genxiao Li ◽  
Zhaohui Sun ◽  
Hengjie Luan ◽  
Chuanzheng Liu ◽  
...  
Keyword(s):  
Side Wall ◽  
Horizontal Displacement ◽  
Middle Part ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Soil Nails ◽  
Factors Affecting ◽  
Composite Soil Nailing ◽  
Soil Foundation ◽  
The Stability

In special geology conditions such as silt-soil, foundation pits are prone to instability and severe deformation. In this paper, a composite soil nailing structure was studied and its effect on a silt-soil symmetrical foundation pit investigated. The factors affecting the stability of the pit as well as its deformation characteristics were also explored. The results show that excavation depth of the foundation pit has a significant impact on its stability. The soil outside the foundation pit is in the form of a parabola, and the uplift of the soil mainly occurs at the bottom. The horizontal displacement of soil on the side wall of the foundation pit presents a “bulk belly” form. In addition, the axial force of soil nails is larger in the middle part, and smaller at both ends in the shape of a spindle. Moreover, the horizontal displacement is positively correlated with the inclination and spacing of the soil nails, but negatively correlated with the diameter and depth of the mixing pile inlay. Furthermore, the inclination and spacing of the soil nails, the diameter, and embedded depth of the mixing pile have their own critical values for stability of the foundation pit. Specifically, in this paper, with respect to soil nails, inclination should be below 30° and prestress value should not exceed 20 kN. With respect to the mixing pile, the diameter should be less than 1.5 m; when the embedded depth of the mixing pile exceeds the critical depth, the limiting effect of the mixing pile on horizontal displacement is not significant. This research provides important takeaways for the design of a composite soil nailing structure for symmetrical foundation pits.

Finite Element Simulation and Stability Analysis of Composite Soil Nailing

2014 ◽  
Vol 580-583 ◽  
pp. 83-88 ◽  
Author(s):  
Jie Zhao ◽  
Ling Li Wang
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Soil Nailing ◽  
Deep Excavation ◽  
Soil Nail ◽  
Element Simulation ◽  
Normal Soil ◽  
Composite Soil Nailing ◽  
The Difference ◽  
The Stability

Under the condition of plane strain, a 2D elastoplastic FEM is used to analyze the behavior of composite soil nailing bracing of deep excavation, then finite element method of stability analysis is applied to evaluate the stability of the soil-nail wall. The authors analyzed the difference between composite soil nailing and normal soil nailing. Through analyzing the effect of bracing parameters on the deformation behavior and stability of the excavation, some useful conclusions are obtained to provide certain references for the design and construction of composite soil nailing.

scholarly journals STUDI PENGARUH KEMIRINGAN, JARAK, DAN PANJANG SOIL NAILING TERHADAP STABILITAS LERENG

2020 ◽  
Vol 3 (3) ◽  
pp. 722
Author(s):  
Melin Ester Simorangkir ◽  
Andryan Suhendra
Keyword(s):  
Safety Factor ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Soil Reinforcement ◽  
Soil Nailing ◽  
Soil Layers ◽  
The Third ◽  
South Sulawesi ◽  
The Stability

A landslide happened at a slope in South Sulawesi. The slope has 4 soil layers with a height of 15 m and a slope angle of 69,86°. Stability of the slope needs to be analized with a program based on limit equilibrium to know the value of its safety factor. After being analyzed, the safety factor of the slope is 0,883, which is less than 1,5. It shows that the slope need a soil reinforcement. For this analysis, soil nailing is being used to be the soil reinforcement. With using soil nailing, the stability of the slope needs to be analyzed again with a program based on limit equilibrium . In each analysis, there are some variations. The first analysis is a variety of nail inclination. The second analysis is a variety of nail spacing. The third analysis is a variety of nail length. The result of the safety factor of all analysis is more than minimal, 1,5. Pada suatu lereng di daerah Sulawesi Selatan, terjadi longsor. Lereng yang mengalami longsor tersebut memiliki 4 lapisan tanah dengan ketinggian lerengnya 15 m dan kemiringan lerengnya 69,86°. Stabilitas lereng perlu dianalisis menggunakan sebuah program berbasis metode kesetimbangan batas untuk mengetahui nilai keamanan lereng tersebut. Setelah dianalisis, diketahui nilai keamanan lereng di bawah 1,5, yaitu 0,883. Nilai keamanan lereng tersebut menunjukkan bahwa lereng tersebut membutuhkan sebuah metode perkuatan tanah. Pada analisis ini, metode perkuatan tanah yang digunakan pada lereng adalah soil nailing. Dengan menggunakan soil nailing, dilakukan analisis stabilitas lereng kembali menggunakan program berbasis metode kesetimbangan batas untuk memperoleh angka faktor keamanan lereng. Di setiap analisis menggunakan soil nailing, digunakan beberapa variasi nail. Analisis stabilitas lereng pertama menggunakan variasi kemiringan nail. Analisis stabilitas lereng kedua menggunakan variasi jarak antar nail. Analisis stabilitas lereng ketiga menggunakan variasi panjang nail. Hasil akhir faktor keamanan lereng setelah dilakukan semua analisis adalah lebih dari 1,5.

scholarly journals Modelling discrete soil reinforcement in numerical limit analysis

2013 ◽  
Vol 50 (7) ◽  
pp. 705-715 ◽  
Author(s):  
Samuel D. Clarke ◽  
Colin C. Smith ◽  
Matthew Gilbert
Keyword(s):  
Limit Analysis ◽  
Limit Equilibrium ◽  
Analysis Procedure ◽  
Soil Reinforcement ◽  
Collapse Mechanism ◽  
Analysis Method ◽  
Soil Nails ◽  
British Standard ◽  
Soil Nail ◽  
Design Specifications

Soil reinforcement is widely used in geotechnical engineering. While there are various means of accounting for the presence of soil reinforcement in limit analysis and limit equilibrium type calculations, these are often highly problem-specific. In this paper, a general means of incorporating soil reinforcement within numerical limit analysis calculations is presented. A key feature of this implementation is that the reinforcement is modelled “in parallel” with the soil model, which allows the soil to flow past the reinforcement as might occur in soil nailing. To illustrate this, the “discontinuity layout optimization” (DLO) numerical limit analysis procedure is used, and the efficacy of the approach is evaluated via application to reinforced slope problems involving rigid soil nails under plane strain conditions. The analyses are calibrated against a two-part wedge analysis method, as presented in British Standard BS 8006:1995 or AASHTO’s LRFD bridge design specifications. It is shown that the DLO-based procedure produces identical results only when the two-part wedge collapse mechanism is prescribed in advance (achieved by artificially strengthening the soil except along pre-defined failure planes). A more critical mechanism is otherwise predicted, with the soil strength at collapse required to be approximately 10% higher than predicted by the two-part wedge method (or alternatively, soil nail lengths required to be approximately 20% greater).

Influence of soil nail orientations on stabilizing mechanisms of loose fill slopes

2013 ◽  
Vol 50 (12) ◽  
pp. 1236-1249 ◽  
Author(s):  
C.Y. Cheuk ◽  
K.K.S. Ho ◽  
A.Y.T. Lam
Keyword(s):  
Earth Pressure ◽  
Slope Movement ◽  
Numerical Analyses ◽  
Soil Nails ◽  
Soil Nail ◽  
Static Liquefaction ◽  
Liquefaction Failure ◽  
Loose Fill ◽  
Typical Design

Soil nailing has been used to upgrade substandard loose fill slopes in Hong Kong. Due to the possibility of static liquefaction failure, a typical design arrangement comprises a structural slope facing anchored by a grid of soil nails bonded into the in situ ground. Numerical analyses have been conducted to examine the influence of soil nail orientations on the behaviour of the ground nail–facing system. The results suggest that the use of steeply inclined nails throughout the entire slope could avoid global instability, but could lead to significant slope movement especially when sliding failure prevails, for instance, due to interface liquefaction. The numerical analyses also demonstrate that if only subhorizontal nails are used, the earth pressure exerted on the slope facing may cause uplift failure of the slope cover. To overcome the shortcomings of using soil nails at a single orientation, a hybrid nail arrangement comprising nails at two different orientations is proposed. The numerical analyses illustrate that the hybrid nail arrangement would limit slope movement and enhance the robustness of the system.

On Numerical Simulation of the Stepped Soil-Nail Wall

2013 ◽  
Vol 353-356 ◽  
pp. 692-695
Author(s):  
Chang Zhi Zhu ◽  
Quan Chen Gao
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Internal Force ◽  
Numerical Results ◽  
Analysis Model ◽  
Foundation Pit ◽  
Soil Nails ◽  
Soil Nail ◽  
Soil Nail Wall ◽  
Design And Construction

Based on an Engineering Example which was supported by the stepped soil-nail wall, a numerical analysis model was established by FLAC3D,and the process of the excavation and supporting was simulated, and the numerical results of the soil nails internal force and foundation pit deformation were obtained. The simulated result was consistent with the measured results. It shows that the method of FLAC3D numerical analysis can be used to the numerical analysis of foundation pit excavation and supporting, and it will provide the basis for the design and construction of practice project.

Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

2013 ◽  
Author(s):  
Constanze Schilder ◽  
Harald Kohlhoff ◽  
Detlef Hofmann ◽  
Frank Basedau ◽  
Wolfgang R. Habel ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Strain Sensors ◽  
Fibre Optic ◽  
Concrete Piles ◽  
Reinforced Concrete Piles ◽  
Pile Testing

QUALITY MANAGEMENT IN THE PRODUCTION OF REINFORCED CONCRETE PRODUCTS FOR AGRICULTURAL FACILITIES

2020 ◽  
Author(s):  
E.A. Shlyakhova ◽  
◽  
I.A. Serebryanaya ◽  
A.V Serdyukova
Keyword(s):  
Reinforced Concrete ◽  
Quality Management ◽  
Business Process ◽  
Process Map ◽  
Concrete Piles ◽  
Reinforced Concrete Piles ◽  
Inputs And Outputs

The article provides an example of regulation of the main business process on the example of the process of "Production of reinforced concrete piles". A process map has been developed and the main inputs and outputs have been identified, and an example of drawing up a business process passport has been developed&

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