Simulation Analysis on Tension and Deformation of Composite Soil Nailing

2013 ◽  
Vol 405-408 ◽  
pp. 182-186 ◽  
Author(s):  
Yan Lin Zhao ◽  
Hao Bin Zhang ◽  
Qing Pan Zhu ◽  
Dong Chen
Keyword(s):  
Simulation Analysis ◽  
Slip Surface ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Initial Stress Field ◽  
Composite Soil Nailing ◽  
The Stability ◽  
The One ◽  
Backward Shifts ◽  
Prestressed Anchor

For studying the mechanism of the composite soil nailing, this paper applies FLAC-3D to simulate pure soil nailing, soil nailing-soil anchor, soil nailing-micro pile-soil anchor. The analytical results as follows: (1)Because of the anchoring of the anchor, the axial tension of soil nailing in each row is much smaller than the one in the pure soil nailing supporting, and the tension of soil nailing which are closed to soil anchor decreases obviously. (2)The extrusion action of prestressed anchor makes the potential slip surface backward shifts and the sliding radius increases, which is better for the stability of foundation pit side (3)Micro-pile increases the strength of the soil in a certain range and improves the initial stress field before the excavation. (4)The inner force of the whole soil nailing and the prestress anchor declines but the drop is not large after the establishment of the micro-pile support in advance. (5)Prestressed anchor and micropile play a very important role in controlling the deformation of foundation pit.

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.

scholarly journals Bearing Characteristics of Moso Bamboo Micropile-Composite Soil Nailing System in Soft Soil Areas

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Zhihe Cheng ◽  
Yousheng Deng
Keyword(s):  
Axial Force ◽  
Slip Surface ◽  
Soft Soil ◽  
Side Wall ◽  
Moso Bamboo ◽  
Shallow Foundation ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Soil Nails ◽  
Composite Soil Nailing

Based on the characteristics of moso bamboo including high short-term strength, stable performance, and ability to provide temporary support for shallow foundation pits in soft soil, the stress characteristics and supporting effects of the ecological composite supporting system have been explored through model tests and numerical calculation analysis of the moso bamboo micropile-composite soil nailing structure. The results showed that the bamboo pile can effectively control the horizontal deformation of the side wall of the foundation pit and the ground surface settlement, achieving a relatively satisfactory supporting effect. Furthermore, the bamboo pile has visibly bent in middle and lower parts, where the regional shear point is most likely to appear, the axial force of the soil nail is distributed in an oval pattern with a smaller force on both sides and a larger force in the middle part, the maximum axial strain is 447.3 με, and the axial force of the soil nails in each row follows a similar trend. The synergy of piles and soil nails can delay the formation of the slip surface, therefore enhancing the overall bearing capacity of the foundation pit. These results can shed light on the support mechanism and engineering design of bamboo piles in shallow soft soil foundation pits.

MODELING THE ROLE OF DISSOLVED OXYGEN-DEPENDENT BACTERIA ON BIODEGRADATION OF ORGANIC POLLUTANTS

2014 ◽  
Vol 07 (01) ◽  
pp. 1450008 ◽  
Author(s):  
J. B. SHUKLA ◽  
ASHISH GOYAL ◽  
P. K. TIWARI ◽  
A. K. MISRA
Keyword(s):  
Dissolved Oxygen ◽  
Water Body ◽  
Logistic Model ◽  
Simulation Analysis ◽  
Organic Pollutant ◽  
The Other ◽  
Nonlinear Mathematical Model ◽  
The Stability ◽  
The One

In this paper, a nonlinear mathematical model is proposed and analyzed to study the role of dissolved oxygen (DO)-dependent bacteria on biodegradation of one or two organic pollutant(s) in a water body. In the case of two organic pollutant(s), it is assumed that the one is fast degrading and the other is slow degrading and both are discharged into the water body from outside with constant rates. The density of bacteria is assumed to follow logistic model and its growth increases due to biodegradation of one or two organic pollutant(s) as well as with the increase in the concentration of DO. The model is analyzed using the stability theory of differential equations and by simulation. The model analysis shows that the concentration(s) of one or both organic pollutant(s) decrease(s) as the density of bacteria increases. It is noted that for very large density of bacteria, the organic pollutant(s) may be removed almost completely from the water body. It is found that simulation analysis confirms the analytical results. The results obtained in this paper are in line with the experimental observations published in literature.

Reliability Analysis of Stability of Foundation Pit Supported by Composite Soil Nailing

2010 ◽  
Vol 168-170 ◽  
pp. 2481-2487
Author(s):  
Yan Lin Zhao ◽  
Wei Guang An
Keyword(s):  
Global Stability ◽  
Reliability Index ◽  
Limit Equilibrium ◽  
Random Variables ◽  
Optimization Method ◽  
Soil Nailing ◽  
Sliding Surface ◽  
Foundation Pit ◽  
Disturbing Force ◽  
Composite Soil Nailing

Based on the limit equilibrium theory and the circular slip surface method, the state equation of limit equilibrium and the calculation model of the most dangerous sliding surface for inner global stability of foundation pit supported by the prestressed anchor composite soil nailing is established with the disturbing force method. And the searching and solving method of the most dangerous sliding surface is optimized with the SLP optimization method and the simplex optimization method. Then with the mechanical parameters of soil as random variables, the reliability index of inner global stability of foundation pit is calculated with the design checking point method. Finally, a practical project is used to analyze the sensitivity of the reliability index to the coefficients of variability of all random variables.

Numerical Analysis of Composite Soil Nailing Wall

2014 ◽  
Vol 1065-1069 ◽  
pp. 48-52
Author(s):  
Shu Long Zhang ◽  
Fen Ting Lu
Keyword(s):  
Three Dimensional ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Soil Nailing ◽  
Construction Process ◽  
Three Dimensional Model ◽  
Foundation Pit ◽  
Finite Element Software ◽  
Ground Surface Settlement ◽  
Composite Soil Nailing

Abstract. The horizontal displacement of soil in slope and the change law of ground surface settlement are dynamically analyzed by building three dimensional-model of foundation pit with the finite element software, ABAQUS, to simulate the construction process of excavation and support, to figure out the influence of micro pile and waterproof curtain on composite soil nailing wall. The study indicates that mechanical model of soil nailing, waterproof curtain, micro pile, pre-stressed anchor interacting with soil can better simulate the construction process of composite soil nailing wall support and have higher calculation accuracy. The calculation can provide a reference for the design and construction of composite soil nailing wall.

FEM Analysis of Composite Soil-Nailing Considering Tensile Failure

2011 ◽  
Vol 105-107 ◽  
pp. 1488-1491 ◽  
Author(s):  
Zhi Gang Yan
Keyword(s):  
Finite Element ◽  
Tensile Failure ◽  
Structure Characteristic ◽  
Interface Element ◽  
Good Precision ◽  
Soil Nailing ◽  
Nonlinear Fem ◽  
Foundation Pit ◽  
Element Analysis ◽  
Composite Soil Nailing

Composite soil-nailing is a new technology developed from abroad in recent years, to be used in excavation of soil, slope stability. This paper studied the stress and deformation of composite soil nailing wall by nonlinear FEM. According to the structure characteristic, the finite element analysis for composite soil nailing construction process is carried out. Based on geotechnical elastic-plastic constitutive model, the adopted failure criterion was a composite Drucker-Prager criterion with tension cut-off. A kind of rotational Goodman interface element is employed to simulate the behavior of interface between the soil-mixed cement which forms the barrier of seepage flow along the boundary of foundation pit, and soil ground. Through the comparative analysis with on-site monitoring data, the finite element calculation results have good precision.

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.

Design and Application of Special Slop Retaining

2010 ◽  
Vol 168-170 ◽  
pp. 652-657
Author(s):  
Li Ping Wen ◽  
Su Li Wang ◽  
Xu Ping Zhu
Keyword(s):  
Numerical Analysis ◽  
General Analysis ◽  
Soil Nailing ◽  
Analysis Program ◽  
Deep Foundation ◽  
Traditional Methods ◽  
Foundation Pit ◽  
Soil Nails ◽  
Deep Foundation Pit ◽  
Composite Soil Nailing

Taking the design of composite soil-nailing in deep foundation pit in complex surroundings for example, the paper discusses numerical analysis of soil-nailing using FLAC, a general analysis program of geotechnical engineering, used to predict the displacement and interior force in soil-nailing. Furthermore, a comparison about the interior force in soil nails between the numerical analysis and the traditional methods is made. The measurements show that the numerical analysis is more accurate than traditional methods. The conclusion is drawn that by contrast with the deficiency of traditional methods, more satisfactory results can be got from numerical analysis on composite soil-nailing using the program of FLAC.

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