scholarly journals Contribution of Tea Root Reinforcement to Soil Shear Strength on Slope Stability

2018 ◽  
Vol 4 (1) ◽  
pp. 13
Author(s):  
Mukhsin Abubakar
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Tensile Stress ◽  
Soil Condition ◽  
Soil Mass ◽  
Root Diameter ◽  
Root Reinforcement ◽  
Root Branching ◽  
Soil Shear Strength ◽  
Diameter Differentiation

Roots played important role in the process of stabilizing the soil mass. The geo-mechanical and soil-hydrological aspects on the slope are determined by, one of it, the root reinforcement. The role of root branching series with diameter differentiation is greatly determining its tensile stress. The tensile stress from the interaction between the root and the soil, could it contribute to increasing the shear strength of the slope stability. The purpose of this research was to identify the tensile stress on root branching series that interacted with the soil and created additional cohesion as a shear strength contribution to the slope stability. Testing on the root pulling force was conducted on slope prototype with angle 30o to 40o and has been planted with tea vegetation. A tripod that was completed with strain gauge as the recording instrument was used. Testing was conducted on two and three root branching, also on each unit by observing the diameter. This testing method was done in saturated soil condition. The tensile stress result showed that increasing diameter of the tea root, an increase was noticed, and also result in the equation of TFr = 0.089e0.516d. Root diameter increase on two and three root branching to one unit of tea vegetation showed that the stress increase was significant. When observed, in the root diameter differentiation of 4 mm to 6 mm, the stress on two and three root branching and one unit of tea vegetation were respectively 5.94%, 12.30%, and 35.42%. The contribution of additional cohesion caused by root-soil interaction to soil shear strength apparently could increase slope stability.

scholarly journals Spatio-Temporal Dynamic Architecture of Living Brush Mattress: Root System and Soil Shear Strength in Riverbanks

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 493 ◽  
Author(s):  
Dong Zhang ◽  
Jinhua Cheng ◽  
Ying Liu ◽  
Hongjiang Zhang ◽  
Lan Ma ◽  
...  
Keyword(s):  
Shear Strength ◽  
Root Morphology ◽  
Spatial Scales ◽  
Root Diameter ◽  
Slope Position ◽  
Protective Effects ◽  
Salix Alba ◽  
Ecological Protection ◽  
Soil Shear Strength ◽  
Spatio Temporal

As a basal measure of soil bioengineering, the living brush mattress has been widely applied in riparian ecological protection forest construction. The living brush mattress shows favorable protective effects on riverbanks. However, there are few reports on the root structure and the soil strengthening benefit of the living brush mattress. The present work reports a series of experiments on root morphology and soil shear strength enhancement at the temporal and spatial scales. The object of the study is 24 living brush mattress trees constructed with Salix alba L. ‘Tristis’ (LBS hereafter). Traditional root morphology and mechanical measurement methods were used to collect the parameters. The results showed that the root systems of LBS had the characteristics of symmetry and upslope growth. The roots were mainly distributed in a cylindrical region of the soil (radius × thickness: 0.4 m × 0.5 m) and their biomass increased with different growth rates for the periods from 1 to 5 and from 5 to 7 years. Both age and slope position were factors that influence root growth. The root diameter falls within 0–5 mm, has a significant effect on the soil shear strength and provides a conical-shape potentiation zone to ensure the efficient protection of a riverbank. The results of this study demonstrate that LBS is an efficient and feasible engineering measure in the field of riverbank protection.

scholarly journals Pengujian Geser Limestone Untuk Menghitung Angka Keamanan Terhadap Kelongsoran Di Utama Mandala Pura Uluwatu

2019 ◽  
Vol 24 (1) ◽  
pp. 13
Author(s):  
I Nyoman Ramia ◽  
I Wayan Arya ◽  
I Wayan Wiraga ◽  
I G A G I G A G Suryanegara
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Direct Shear Test ◽  
Shear Test ◽  
Dead Load ◽  
Soil Shear Strength ◽  
Engineering Department ◽  
Sliding Test ◽  
The Stability ◽  
The Temple

The shear strength value is one of the important points in calculation of slope stability. One way to obtain the shear strength value is to do a direct shear test in laboratory. Like the cliff reinforcement study at Utama Mandala Uluwatu temple which is currently experiencing crack, it is necessary to test the shear strength of the limestone material at the cliff of the temple . There is no limestone testing equipment in the laboratory of the Civil Engineering Department, so that innovation is needed on the existing sliding test equipment. In this study innovation was carried out on how to test the soil shear strength so that it could be used to test the limestone shear strength. The test is done by moving two limestone surface that have been formed based on the mold tool which shape is circle. The shear strength slope at Uluwatu temple, which is currently experiencing crack in dry condition is . The shear strength value is used for calculating slope stability at Uluwatu Temple which is currently experiencing crack wich . The calculation used is curved slope stability by only calculate the life load and dead load. From the calculation of the stability of the slope, the safety factor is 1.15.

scholarly journals FUNCTION OF INTERCEPTION, EVAPOTRANSPIRATION AND ROOT REINFORCEMENT OF PLANT ON SLOPE STABILIZATION

2020 ◽  
Vol 15 (1) ◽  
pp. 19-26
Author(s):  
Euthalia Hanggari Sittadewi
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Tree Canopy ◽  
Shear Stresses ◽  
Slope Stabilization ◽  
Root Reinforcement ◽  
Soil Shear Strength ◽  
Positive Effect

The ability of plants to carry out the functions of interception, evapotranspiration and root reinforcement provides an effective and contributes to an increase in slope stability. Canopy has a role in the process of interception related to the reduction of amount the infiltrated water and the rapid fulfilment of soil moisture. Through the evapotranspiration mechanism, plants can reduce pore water pressure in the soil so that the trigger force for landslides can be reduced and the soil will be more stable. The roots mechanically strengthen the soil, through the transfer of shear stresses in the soil into tensile resistance in the roots. Roots also bind soil particles and increase surface roughness, thereby reducing the process of soil displacement or erosion. There is a positive relationship between the density of the tree canopy with the value of rainfall interception, evapotranspiration with a decrease in pore water pressure in the soil and the ability of root anchoring and binding with an increase in soil shear strength, indicating that the function of interception, evapotranspiration and strengthening of plant roots have a positive effect on increasing slope stability. Plants selection that considers the level of interception, the rate of evapotranspiration and root reinforcement by adjusting environmental and slopes conditions will determine the success of slope stabilization efforts by vegetative methods.Keywords : interception, evapotranspiration, root reinforcement, slope stabilization.

scholarly journals Root Tensile Resistance of Selected Pennisetum Species and Shear Strength of Root-Permeated Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Afaff Emhemed Ettbeb ◽  
Zulfahmi Ali Rahman ◽  
Wan Mohd Razi Idris ◽  
Jumaat Adam ◽  
S. Abd. Rahim ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Tensile Force ◽  
Mineral Fertilizer ◽  
Tensile Tests ◽  
Root Diameter ◽  
Slope Instability ◽  
Root Reinforcement ◽  
Significant Relationships ◽  
Peak Shear Stress

It is widely recognized that vegetation plays a significant role in contrasting slope instability through the root reinforcement. The main objectives of this paper are to evaluate the root tensile of selected Pennisetum species, namely, P. pedicellatum (PPd) and P. polystachion (PPl), and to determine the soil shear strength of root-permeated soil from these species. The selected species were initially planted in the polybags using the hydroseeding technique. A mineral fertilizer of NPK ratio 10 : 8 : 10 was adopted in the hydroseeding mixture. Routine watering program was applied twice a day throughout growth observation for six months. Four replications were prepared for each species including a set of control polybags, which contained only soil for reference and comparison. The results of root tensile tests revealed the significant relationships between root diameter and tensile force. In comparison, the PPl was still indicated by higher values of root tensile force than PPd. The presence of roots clearly has contributed to the shear stress of root-permeated soils. The root density based on root biomass measurement attributed to the higher value of peak shear stress as achieved by PPl than PPd. The combined effects of root tensile and the soil shear strengths of this selected species can be used as biological materials in slope protection against erosion.

scholarly journals The Effects of Seismic Coefficient Uncertainty on Pseudo-Static Slope Stability: A Probabilistic Sensitivity Analysis

2021 ◽  
Vol 13 (15) ◽  
pp. 8647
Author(s):  
Dongli Li ◽  
Miaojun Sun ◽  
Echuan Yan ◽  
Tao Yang
Keyword(s):  
Sensitivity Analysis ◽  
Shear Strength ◽  
Slope Stability ◽  
Static Analysis ◽  
Probabilistic Sensitivity Analysis ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Seismic Coefficient ◽  
Soil Shear Strength ◽  
Critical Slope

The method of pseudo-static analysis has been widely used to perform seismic slope stability, in which a seismic coefficient is used to represent the earthquake shaking effect. However, it is important but difficult to select the magnitude of seismic coefficients, which are inevitably subjected to different levels of uncertainties. This paper aimed to study the influences of seismic coefficient uncertainties on pseudo-static slope stability from the perspective of probabilistic sensitivity analysis. The deterministic critical slope height was estimated by the method of upper-bound limit analysis with the method of pseudo-static analysis. The soil shear strength parameters, the slope geometrical parameters (including slope inclinations, slope heights, and the slope widths), the horizontal seismic acceleration coefficient, and the unit weight of soil masses were considered as random variables. The influences of their uncertainty degrees, the correlation relations, and the distribution types of random variables on probabilistic density functions, failure probabilities, and sensitivity analysis were discussed. It was shown that the uncertainty degrees greatly impact the probability density distributions of critical slope heights, the computed failure probabilities, and Sobol’ index, and the horizontal seismic coefficient was the second most important variable compared to the soil shear strength parameters.

Slope stability thresholds for vegetated hillslopes: a composite model

2002 ◽  
Vol 39 (4) ◽  
pp. 849-862 ◽  
Author(s):  
Jagath C Ekanayake ◽  
Christopher J Phillips
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Plant Density ◽  
Composite Model ◽  
Energy Approach ◽  
Water Infiltration ◽  
Wetting Front ◽  
Tree Roots ◽  
Soil Shear Strength ◽  
The Stability

Location of the critical shear plane (CSP) plays a major role in determining landslide-initiation thresholds. Depth to the CSP increases as the soil shear strength increases. Tree roots provide a significant strength contribution to soil shear strength. Our objective is to understand how vegetation can be used to increase landslide-initiation thresholds by changing the location of the CSP. This will enable us to select and compare combinations of plant species and densities to suit any given situation to increase landslide-initiation thresholds and improve slope stability. The CSP location is estimated incorporating available root cross-sectional area – root depth data in the stability analysis in terms of energy. The energy approach has been developed to take into account the contribution of the roots to soil strength. Generalization of the original energy approach is required to enable its use outside our study areas. Once depth to the CSP is found, the time for the wetting front to reach it is found using a soil-water infiltration model. The composite model described may be used as a simple tool to choose the most appropriate plant density to maximize the stability of a given hillslope. A worked example of the model demonstrates how the approximate thresholds for different hillslopes with known plant densities under different climatic conditions are estimated.Key words: slope stability, safety factor, roots, energy, threshold.

scholarly journals Contribution of root tensile of Pennisetum polystachion on shear strength of sandy soil in slope bio-engineering technique

2021 ◽  
Vol 42 (3(SI)) ◽  
pp. 857-864
Author(s):  
Z.A. Rahman ◽  
◽  
A.E. Ettbeb ◽  
W.M.R. Idris ◽  
S.N.A. Tarmidzi ◽  
...  
Keyword(s):  
Shear Strength ◽  
Sandy Soil ◽  
Slope Failure ◽  
Tensile Force ◽  
Root Diameter ◽  
Slope Instability ◽  
Strength Parameter ◽  
Experimental Program ◽  
Soil Shear Strength ◽  
Bio Engineering

Aim: In soil bio-engineering, plant has been widely adopted as important material in promoting sustainable ecological function in slope instability measures. Plant canopy provides shelter and at subsurface level, root networking attributes toward stability of soil against erosion and slope failure. To investigate the potential of selected P. polystachion as biological material in soil bio-engineering for improving the soil shear strength of sandy soil planted with P. polystachion. Methodology: The selected species was initially planted using hyroseeding technique on studied plots which facilated with and without fiber netting (made of paddy straw). A control plot was also prepared for reference of this study. The plots were routinely watered twice a day for six months before experimental program was scheduled for determining of root tensile and soil shear strength tests. Results: The root tensile strength of P. polystachion exhibited a positive significant relationship between root tensile force and root diameter. The shear strength of soil was affected by the presence of root if compared to that of soil without root (control). Biomass analysist also agree with the soil water content, ws. High biomass contributed to the increase in the values of soil shear strength parameter of cohesive, c and angle of friction, q for root-permeated soil with P. polystachion. Interpretation: This study has suggested that the potential application of this selected species for slope vegetation in improving the erosion control and slope stability in soil-bioengineering scheme.

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