Stability of the Walls in Nails Soil

2011 ◽  
Vol 324 ◽  
pp. 380-383
Author(s):  
Fatima Zohra Benamara ◽  
Lazhar Belabed
Keyword(s):  
Mechanical Model ◽  
Shear Force ◽  
Retaining Wall ◽  
Failure Model ◽  
General Aspect ◽  
Soil Nail ◽  
The Stability

Developed as from the seventies, the nailing of the soils is a technique, which makes it possible to carry out a retaining wall of excavation by using the soil in place and installing the passive bars called nails. The main object of this work is to study the stability of the walls in soil nailed lived overall rupture facing-soil-nail. In order to find the mechanism or the mechanical model most unstable. Give a general aspect to our studies; we also studied a title comparative the classical circular failure model. We have repeatedly determined for each case the maximum shear soil force in the nails Tm. The most unfavourable mechanism (less stable) among all the mechanisms is that for which, the shear force Tm reached a maximum. Another analysis of the stability of wall in nailed soil was made by means of the software Geo4 and compared with the kinematics method.

scholarly journals Stability of Anchored Retaining Walls Under Seismic Loading Conditions to Obtain Minimal Anchor Lengths Using The Improved Failure Model

2020 ◽  
Vol 30 (3) ◽  
pp. 214-233
Author(s):  
Fatima Zohra Benamara ◽  
Ammar Rouaiguia ◽  
Messaouda Bencheikh
Keyword(s):  
Retaining Wall ◽  
Retaining Walls ◽  
Seismic Load ◽  
Failure Model ◽  
New Model ◽  
Anchor Length ◽  
Earth Pressures ◽  
Internal Forces ◽  
The Stability ◽  
Minimum Safety Factor

Abstract Anchored retaining walls are structures designed to support different loading applied in static and dynamic cases. The purpose of this work is to design and study the stability of an anchored retaining wall loaded with different seismic actions to obtain minimal anchor lengths. Mononobe-Okabe theory has been applied for the evaluation of seismic earth pressures developed behind the anchored wall. Checking the dynamic stability of anchored retaining walls is usually done using the classic Kranz model. To take into consideration the effects of the internal forces developed during failure, we have proposed a new model, based on the Kranz model, which will be used as the Kranz model to find the critical angle failure performed iteratively until the required horizontal anchor length is reached for a minimum safety factor. The results of this study confirm that the effect of the seismic load on the design of an anchored retaining wall, and its stability, has a considerable influence on the estimation of anchor lengths. To validate the modifications made to the new model, a numerical analysis was carried out using the Plaxis 2D software. The interpretation of the obtained results may provide more detailed explanation on the effect of seismic intensities for the design of anchored retaining walls.

scholarly journals EVALUASI STABILITAS DINDING PENAHAN TANAH TIPE KANTILEVER DI DESA NGROTO, KECAMATAN PUJON, KABUPATEN MALANG

2021 ◽  
Vol 15 (1) ◽  
pp. 22
Author(s):  
Suhudi Suhudi ◽  
Simplisius Ehok
Keyword(s):  
Bearing Capacity ◽  
Water Level ◽  
Safety Factor ◽  
Shear Force ◽  
Rainfall Intensity ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Total Cost ◽  
Normal Water ◽  
The Stability

AbstractWavy topographical conditions with high rainfall intensity cause cantilever type retaining wall on Jalan Brigjen Abdul Manan Wijaya in Ngroto village, Pujon District, Malang Regency, which borders the Konto River avalanche. The stability of the retaining wall can be expressed as Fs (Savety Factor). Factor value the security that is reviewed is the Fs bolster, namely the safety factor against the overthrowing force, the Fs shear is the safety factor against the shear force at the base of the retaining wall, Fs, the bearing capacity of the soil is a factor safety of soil bearing capacity. The purpose of this evaluation is to determine the wall planning cantilever type retaining wall and evaluate the stability of cantilever type retaining wall against the dangers of rolling, shearing, soil bearing capacity and knowing the budget plan for wall planning Cantilever type retaining wall. The result of this evaluation shows the cantilever retaining wall with dimensions H = 7, B = 3.5 Ta = 0.5 Tb = 0.7 D = 1 declared safe with the safety value for normal water level fs slide 1.8> 1.5 (safe), fs roll 2> 1.5 (safe), fs ground bearing capacity 186.8> 4752.86 (safe). Water face flood fs shear 2,6> 1,5 (safe) fs rolling 2,3> 1,5 (safe) fs soil bearing capacity 186.8> 4752.86 (safe). The total cost required for the construction of a cantilever type retaining wall of length 20 m T = 7 width 3.5 m for Rp. 290,570,000.Keywords: Retaining walls, Dimensions, Stability of retaining walls

PSEUDOSTATIC DESIGN FACTORS FOR STABILITY OF WATERFRONT-RETAINING WALL DURING EARTHQUAKE

2010 ◽  
Vol 04 (04) ◽  
pp. 387-400 ◽  
Author(s):  
DEEPANKAR CHOUDHURY ◽  
SYED MOHD AHMAD
Keyword(s):  
Retaining Wall ◽  
Pressure Ratio ◽  
Free Water ◽  
Hydrodynamic Pressure ◽  
Wall Friction ◽  
Sliding Stability ◽  
The Stability ◽  
Seismic Forces ◽  
Design Factors ◽  
Similar Kind

The paper presents a methodology for seismic design of rigid watferfront-retaining wall and proposes simple design factors for the sliding stability under seismic condition. Conventional pseudostatic approach has been used for the calculation of the seismic forces, while for the calculation of the hydrodynamic pressure, Westergaard's approach has been used. In addition, the hydrodynamic force has been considered from both the upstream and downstream sides of the waterfront-retaining wall under free water condition of the backfill. Simplified expression for the calculation of the equivalent weight of the wall which would be needed to maintain sliding stability is presented. It has been observed that the presence of water both on the upstream and downstream sides of the wall has serious destabilizing effect on the stability of the wall. It is noticed that as the height of the water inside the backfill increased from 0.00 to a height equal to the height of the wall itself, i.e., the backfill is fully submerged, the weight of the wall needed for the later case is around 3 times more than what would be needed for the former case. Similar observations were also made by varying other parameters like the horizontal and vertical seismic acceleration coefficients, height of the water on the upstream side of the wall, and soil and wall friction angles. The pore pressure ratio and the inclination of the ground, however, did not have significant effect on the results. Due to nonavailability of the results of similar kind in literature, an exact comparison for the present results could not be made. Only partial comparison of the present results is made with an already existing methodology for the dry backfill case only, in which no presence of water has been considered on the other side of the wall. This comparison shows a good agreement with the present results. The proposed pseudostatic design factors for the case of wet backfill with the presence of water on both sides of the wall are claimed to be unique.

scholarly journals Mechanical Modeling of Roof Fracture Instability Mechanism and Its Control in Top-Coal Caving Mining under Thin Topsoil of Shallow Coal Seam

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Peilin Gong ◽  
Tong Zhao ◽  
Kaan Yetilmezsoy ◽  
Kang Yi
Keyword(s):  
Coal Seam ◽  
Mechanical Model ◽  
Main Roof ◽  
Stability Control ◽  
Hydraulic Support ◽  
Rock Stability ◽  
Shallow Coal Seam ◽  
Minimum Height ◽  
The Stability ◽  
Working Resistance

This study aimed to explore the safe and efficient top-coal caving mining under thin topsoil of shallow coal seam (SCS) and realize the optimization of hydraulic support. Numerical simulation and theoretical analysis were used to reveal the stress distribution of the topsoil, the structure characteristics of the main roof blocks, and the development of the roof subsidence convergence. Step subsidence of the initial fractured main roof after sliding destabilization frequently existed, which seriously threatened the safety of the hydraulic supports. Hence, a mechanical model of the main roof blocks, where the topsoil thickness was less than the minimum height of the unloading arch, was established, and the mechanical criterion of the stability was achieved. The working resistance of the hydraulic support was calculated, and the reasonable type was optimized so as to avoid crushing accident. Findings of the present analysis indicated that the hydraulic support optimization was mainly affected by fractured main roof blocks during the first weighting. According to the block stability mechanical model based on Mohr–Coulomb criterion, the required working resistance and the supporting intensity were determined as 4899 kN and 0.58 MPa, respectively. The ZZF5200/19/32S low-position top-coal caving hydraulic support was selected for the studied mine and support-surrounding rock stability control of thin-topsoil SCS could be achieved without crushing accident.

scholarly journals Evolution Laws of Mining-induced Stress in Floor Strata and Its Influence on the Stability of a Floor Roadway Affected by Overhead Mining

2020 ◽  
Vol 24 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Pu Wang ◽  
Lishuai Jiang ◽  
Changqing Ma ◽  
Anying Yuan
Keyword(s):  
Numerical Simulation ◽  
Mechanical Model ◽  
Scientific Basis ◽  
Pull Out ◽  
Induced Stress ◽  
Working Face ◽  
Geological Conditions ◽  
Evolution Laws ◽  
The Stability

The study of evolution laws of the mining-induced stress in floor strata affected by overhead mining is extremely important with respect to the stability and support of a floor roadway. Based on the geological conditions of the drainage roadway in the 10th district in a coalmine, a mechanical model of a working face for overhead mining over the roadway is established, and the laws influencing mining stress on the roadway in different layers are obtained. The evolution of mining stress in floor with different horizontal distances between the working face and the floor roadway that is defined as LD are examined by utilizing UDEC numerical simulation, and the stability of roadway is analyzed. The results of the numerical simulation are verified via on-site tests of the deformation of the surrounding rocks and bolts pull-out from the drainage roadway. The results indicate that the mining stress in floor is high, which decreases slowly within a depth of less than 40 m where the floor roadway is significantly affected. The mining stress in the floor increases gradually, and the effect of the mining on the roadway is particularly evident within 0 m ≤ LD ≤ 40 m. Although the floor roadway is in a stress-relaxed state, the worst stability of the surrounding rocks is observed during the range -20 m ≤ LD < 0 m, in which the negative value indicates that the working face has passed the roadway. The roadway is affected by the recovery of the abutment stress in the goaf when -60 m ≤ LD <20 m, and thus it is important to focus on the strengthening support. The results may provide a scientific basis for establishing a reasonable location and support of roadways under similar conditions.

scholarly journals Stability Assessment of Earth Retaining Structures under Static and Seismic Conditions

2019 ◽  
Vol 4 (2) ◽  
pp. 15
Author(s):  
Nimbalkar ◽  
Pain ◽  
Ahmad ◽  
Chen
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Accurate Estimation ◽  
Engineering Practice ◽  
Active Earth Pressure ◽  
Stability Assessment ◽  
Linear Distribution ◽  
Backfill Soil ◽  
The Stability ◽  
Seismic Earth Pressure

An accurate estimation of static and seismic earth pressures is extremely important in geotechnical design. The conventional Coulomb’s approach and Mononobe-Okabe’s approach have been widely used in engineering practice. However, the latter approach provides the linear distribution of seismic earth pressure behind a retaining wall in an approximate way. Therefore, the pseudo-dynamic method can be used to compute the distribution of seismic active earth pressure in a more realistic manner. The effect of wall and soil inertia must be considered for the design of a retaining wall under seismic conditions. The method proposed considers the propagation of shear and primary waves through the backfill soil and the retaining wall due to seismic excitation. The crude estimate of finding the approximate seismic acceleration makes the pseudo-static approach often unreliable to adopt in the stability assessment of retaining walls. The predictions of the active earth pressure using Coulomb theory are not consistent with the laboratory results to the development of arching in the backfill soil. A new method is proposed to compute the active earth pressure acting on the backface of a rigid retaining wall undergoing horizontal translation. The predictions of the proposed method are verified against results of laboratory tests as well as the results from other methods proposed in the past.

Pregnant Mechanism and Mechanical Model of Rock Landslides in Chair-Shaped Cataclinal Bank Slopes

2014 ◽  
Vol 580-583 ◽  
pp. 2589-2599
Author(s):  
Xian Chun Ma ◽  
Xi Chang Chen ◽  
You Jun Feng
Keyword(s):  
Mechanical Model ◽  
Critical Value ◽  
Control Measures ◽  
Monitoring Methods ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Sliding Mechanism ◽  
Groundwater Supply ◽  
Rock Landslide ◽  
The Stability

The pregnant and sliding mechanism was firstly compared between Vajont and Qianjiangping large rock landslides, which happened in the chair-shaped cataclinal bank slopes. And then the essence of the landslides occurred was deduced. The pregnant and sliding process of the landslides was showed two stages. First, after the first impoundment of the reservoir, the soil and shallow rock at the front of the landslides were slipped and then caused posterior margin of the deep latent sliding surface cracks. So the groundwater supply condition was significantly changed. Second, with the rapidly increase of the groundwater recharge, its pressure on the front of the landslides was also rapidly rise to the critical value which the landslides occurred. Afterwards, the stability mechanical model of the chair-shaped cataclinal bank slopes and critical value formula of the groundwater pressure were established on the basis of the stability mechanical model of general chair-shaped cataclinal slopes, added reservoir water level which was a dynamic load. While working procedures to determine the groundwater pressure was put forward. Last, the theory was certified validity take Liangshuijing rock landslide of the Three Gorges Project area as an example and the monitoring methods and control measures for the landslide were proposed.

Performance of cement-stabilized retaining walls

2005 ◽  
Vol 42 (3) ◽  
pp. 876-891 ◽  
Author(s):  
M A Ismail
Keyword(s):  
Finite Element ◽  
Retaining Wall ◽  
Friction Angle ◽  
Experimental Program ◽  
Centrifuge Model Test ◽  
Element Analysis ◽  
Centrifuge Testing ◽  
Load Carrying ◽  
The Stability ◽  
Surrounding Soil

This paper investigates the performance of a cement-stabilized retaining wall as a potentially economic solution for supporting vertical cuts in roads and embankments. This investigation was carried out through a comprehensive numerical and experimental program in which the stabilized wall was treated as a c′–ϕ soil. To optimize the design of the stabilized wall, a plane-strain finite element analysis was carried out, using the PLAXIS code, in a parametric study that varied the wall geometry and the shear strength parameters for both the wall and its surrounding soil. The performance of the stabilized retaining wall was verified by a centrifuge model test carried out at an equivalent acceleration of 67g for a sand treated with 3% Portland cement. The results have shown that the load-carrying capacity of the wall is affected primarily by both the cementation of the wall and the friction angle of the surrounding soil. There exists a threshold of cementation beyond which the stability does not increase when the failure mechanism is located completely inside the in situ soil. This critical cementation appears to be a crucial factor in maintaining an economic design for this type of wall. Centrifuge test results confirmed the satisfactory behaviour of cement-stabilized retaining walls.Key words: cement stabilization, retaining wall, cohesion, finite element, centrifuge testing.

The Stability Analysis of Reinforced Earth Retaining Wall System and the Study of its Reinforcement Optimization

2011 ◽  
Vol 90-93 ◽  
pp. 2389-2392
Author(s):  
Hai Yan Ju ◽  
Gui Qing Gao ◽  
Jian Hua Li ◽  
Jiang Qian Zhao ◽  
Zhang Ming Li
Keyword(s):  
Cross Sections ◽  
Design Method ◽  
Retaining Wall ◽  
Physical Behavior ◽  
Reinforced Earth ◽  
Slope Treatment ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship ◽  
System Program

Because the relationship is not considered between physical behavior and cross sections of bars, the conventional reinforced earth retaining wall design based on constant value would lead to some limitations: the haul-resistant coefficient of the top wall is not enough, but it goes beyond at the bottom of retaining wall. In the paper, considering the SARMA method, based on computing formula of traditional slope stability, the detailed programme is realized by the language of FORTRAN, it can make up deficiency that lies in the tradition reinforced earth retaining wall by considering the relationship of physical behavior and cross sections, lengths and layers of bars. Finally, the system program has been applied to a slope treatment project in Guangzhou. Compared with the design method of traditional regulations, it is demonstrated that the optimum length required is obtained, the cross section and length of bars are fully used, and the design is simplified.

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