scholarly journals Study on the Stability of Slopes Reinforced by Composite Vegetation Combined with a Geogrid under Rainfall Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Qizhi Hu ◽  
Yong Zhou ◽  
Gaoliang Tao
Keyword(s):  
Southern China ◽  
Maximum Displacement ◽  
Protection Effect ◽  
Tree Distribution ◽  
Stability Of Slopes ◽  
Protection Method ◽  
Ecological Protection ◽  
Reinforced Slopes ◽  
The Stability ◽  
Dense Tree

The planting of shrubs and trees on geogrid-reinforced slopes is an important ecological slope protection method that is frequently implemented in the rainy areas of southern China. First, this paper analyzes the soil-fixing principle of the geogrid and root system and demonstrates the feasibility of using composite vegetation of shrubs and trees to reinforce the slope with a geogrid. Using the Yushi Expressway project in Guizhou, we conducted a stability analysis of slopes under different working conditions and different reinforcement modes. We determined that the ecological protection method of combining composite vegetation with a geogrid can effectively increase the stability of slopes. The maximum displacement of the ecological slope under rainfall conditions was reduced by 82% compared with the original slope, and the overall stability was improved by 35%. Four factors affect the slope stability: the depth of shrub reinforcement, depth of anchorage of trees, distribution of trees, and spacing of the geogrids. An orthogonal analysis considering these 4 factors with 3 levels was implemented. The following optimal combination was obtained to ensure ecological protection under rainfall conditions: a shrub reinforcement depth of 0.6 m, a tree anchorage depth of 3 m, a grid spacing of 0.4 m, and a top-sparse and bottom-dense tree distribution. The combined slope protection schematic was applied to the Yushi Expressway project in Guizhou, and a strong reinforced slope protection effect was observed.

scholarly journals Application of Polymer Curing Agent in Ecological Protection Engineering of Weak Rock Slopes

2019 ◽  
Vol 9 (8) ◽  
pp. 1585 ◽  
Author(s):  
Ding Yao ◽  
Guoping Qian ◽  
Jiawu Liu ◽  
Jialiang Yao
Keyword(s):  
Slope Instability ◽  
Weak Rock ◽  
Curing Agent ◽  
Rock Slopes ◽  
Acrylic Emulsion ◽  
Finite Element Software ◽  
Stability Of Slopes ◽  
Ecological Protection ◽  
Polymer Curing ◽  
The Stability

Under the action of water, weak rock slopes easily expand and the strength and stiffness decrease, which results in slope instability. The styrene–acrylic emulsion cement-matrix composite, a new type of polymer curing agent, was developed for the curing and treatment of weak rock slopes. The strength-reduction factor method and ANSYS finite element software were used to calculate and analyze the stability of slopes before and after protection. The stability safety factor of weak rock after protection increased by 30% from 2.0 to 2.6. In order to evaluate the performance of the polymer curing agent, the mixture test was carried out in the laboratory. It was found that the waterproofness, hydrophobicity, and microstructure of weak rock slopes with the polymer curing agent can be significantly improved. Finally, the polymer curing agent was adopted and the external-soil spray-seeding technique was used in physical engineering. From test results, it was indicated that the polymer curing agent for weak slopes is beneficial in improving the water-damage resistance of a slope surface and prevent or reduce the softening of weak rock so that plants can grow for a long time. The treatment for weak rock slopes was successfully combined with plant protection, achieving the dual effect of weak rock slope protection and ecological protection.

ASSESSMENT OF PINE CROPS GROWTH IN BAIMAK FORESTRY

2020 ◽  
Vol 37 (3) ◽  
pp. 83-90
Author(s):  
T.Z. Mutallapov ◽  
Keyword(s):  
Scots Pine ◽  
Forest Ecosystem ◽  
Distribution Curve ◽  
Comparative Assessment ◽  
Tree Distribution ◽  
Entire Structure ◽  
Structure Changes ◽  
Large Trees ◽  
Different Types ◽  
The Stability

The article presents the results of evaluating the growth of Scots pine in the Baymak forest area. The analysis of forestry and taxation indicators of Scots pine crops on the studied sample areas is carried out, and a comparative assessment of the growth of forest crops growing in different types of forest is given. Increased competition in plantings leads to the natural decline of stunted trees, which is the result of differentiation in the stand. As a result, its structure changes, the number of large trees increases, and, accordingly, the stability of the forest ecosystem increases. In this regard, the appearance of the tree distribution curve by thickness levels also changes. It becomes more "flat", and its competitive load is more evenly distributed over the entire structure of the stand, and competition is weakened.

scholarly journals Reliability Estimation of Reinforced Slopes to Prioritize Maintenance Actions

2021 ◽  
Vol 18 (2) ◽  
pp. 373
Author(s):  
Farshad BahooToroody ◽  
Saeed Khalaj ◽  
Leonardo Leoni ◽  
Filippo De Carlo ◽  
Gianpaolo Di Bona ◽  
...  
Keyword(s):  
Urban Areas ◽  
Evaluation Method ◽  
Likelihood Function ◽  
Reliability Estimation ◽  
Analytical Models ◽  
Geotechnical Structures ◽  
Reinforced Slopes ◽  
The Stability ◽  
Methods Analytical ◽  
Asset Managers

Geosynthetics are extensively utilized to improve the stability of geotechnical structures and slopes in urban areas. Among all existing geosynthetics, geotextiles are widely used to reinforce unstable slopes due to their capabilities in facilitating reinforcement and drainage. To reduce settlement and increase the bearing capacity and slope stability, the classical use of geotextiles in embankments has been suggested. However, several catastrophic events have been reported, including failures in slopes in the absence of geotextiles. Many researchers have studied the stability of geotextile-reinforced slopes (GRSs) by employing different methods (analytical models, numerical simulation, etc.). The presence of source-to-source uncertainty in the gathered data increases the complexity of evaluating the failure risk in GRSs since the uncertainty varies among them. Consequently, developing a sound methodology is necessary to alleviate the risk complexity. Our study sought to develop an advanced risk-based maintenance (RBM) methodology for prioritizing maintenance operations by addressing fluctuations that accompany event data. For this purpose, a hierarchical Bayesian approach (HBA) was applied to estimate the failure probabilities of GRSs. Using Markov chain Monte Carlo simulations of likelihood function and prior distribution, the HBA can incorporate the aforementioned uncertainties. The proposed method can be exploited by urban designers, asset managers, and policymakers to predict the mean time to failures, thus directly avoiding unnecessary maintenance and safety consequences. To demonstrate the application of the proposed methodology, the performance of nine reinforced slopes was considered. The results indicate that the average failure probability of the system in an hour is 2.8×10−5 during its lifespan, which shows that the proposed evaluation method is more realistic than the traditional methods.

scholarly journals Optimal profile for concave slopes under static and seismic conditions

2016 ◽  
Vol 53 (9) ◽  
pp. 1522-1532 ◽  
Author(s):  
Farshid Vahedifard ◽  
Shahriar Shahrokhabadi ◽  
Dov Leshchinsky
Keyword(s):  
Limit Equilibrium ◽  
Stable Configuration ◽  
Preliminary Evaluation ◽  
Construction Technology ◽  
Stability Of Slopes ◽  
Optimal Profile ◽  
Stabilized Soil ◽  
The Stability ◽  
Comparison Of The Results ◽  
The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

scholarly journals Soil-Root System Withholding Strength for River Bank Stability

2016 ◽  
Vol 77 (1) ◽  
Author(s):  
IR. PROF. DR RUSLAN HASSAN HASSAN ◽  
Ding Ibau
Keyword(s):  
Relative Strength ◽  
Shear Stresses ◽  
Strength Increase ◽  
Maximum Displacement ◽  
River Bank ◽  
Slope Stabilisation ◽  
Shearing Resistance ◽  
The Stability ◽  
Direct Shear Apparatus ◽  
Riverbank Restoration

The ability of vegetation to stabilise soils is frequently employed in slope stabilisation projects including riverbank restoration activity. Soil block samples permeated with roots of Bermuda Grass commonly used for remediation and riverbank restoration were tested in a direct shear apparatus. Shear stress results of rooted soils were compared with results of un-vegetated soil bloc—s with similar soil types. The increase of shear strength was determined by comparing shear stresses at speciic horizontal displacements. The relative strength increase at the same displacement was 27.3 kPa compared to 19.1 kPa for un-vegetated soil at a displacement of 13.3cm (Location 3). The relative strength increase at the same displacement of 13.3cm was 43.5% for Location 1 and 42.4% for Location 2. The shear stresses in most of the blocks with roots were still increasing at the end of the test (maximum displacement of about 15cm). These conservative root biomass values and the shearing resistance obtained can be used in the assessment of the stability of the existing vegetated slopes and in the design of vegetated riverbanks.

scholarly journals The Effects of Hydraulic Properties of Bedrock on the Stability of Slopes

2012 ◽  
pp. 343-349 ◽  
Author(s):  
Amin Askarinejad ◽  
Patrick Bischof ◽  
Francesca Casini ◽  
Sarah M. Springman
Keyword(s):  
Hydraulic Properties ◽  
Stability Of Slopes ◽  
The Stability

scholarly journals Strength Theory Model of Unsaturated Soils with Suction Stress Concept

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Pan Chen ◽  
Changfu Wei ◽  
Jie Liu ◽  
Tiantian Ma
Keyword(s):  
Shear Strength ◽  
Unsaturated Soils ◽  
Theory Model ◽  
Strength Analysis ◽  
New Model ◽  
Suction Stress ◽  
Strength Change ◽  
Stability Of Slopes ◽  
Moisture State ◽  
The Stability

A theoretical model is developed for describing the strength property of unsaturated soils. The model is able to predict conveniently the strength changes of unsaturated soils undergoing repeated changes of water content. Suction stress is adopted in the new model in order to get the sound form of effective stress for unsaturated soils. The shear strength of unsaturated soils is dependent on its soil-moisture state based on the results of shear experiments. Hence, the parameters of this model are related tightly to hydraulic properties of unsaturated soils and the strength parameters of saturated soils. The predictive curves by the new model are coincident with experimental data that underwent single drying and drying/wetting cycle paths. Hence, hysteretic effect in the strength analysis is necessary to be considered to predict the change of shear strength of unsaturated soils that underwent drying/wetting cycles. Once the new model is used to predict the change of shear strength, lots of time could be saved due to avoiding heavy and complicated strength tests of unsaturated soils. Especially, the model can be suitable to evaluate the shear strength change of unsaturated soils and the stability of slopes experienced the drying/wetting cycles.

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