scholarly journals Effect of Oriental beech root reinforcement on slope stability (Hyrcanian Forest, Iran)

2014 ◽  
Vol 60 (No. 4) ◽  
pp. 166-173 ◽  
Author(s):  
E. Abdi
Keyword(s):  
Tensile Strength ◽  
Slope Stability ◽  
Root Distribution ◽  
Factor Of Safety ◽  
Power Relationship ◽  
Strength Increase ◽  
Hyrcanian Forest ◽  
Reinforcement Effect ◽  
Root Reinforcement ◽  
Oriental Beech

Vegetation significantly affects hillslope mechanical properties related to shallow landslides and slope stability. The objective of this study was to investigate and quantify the effect of Oriental beech root reinforcement on slope stability. A part of Hyrcanian forest in northern Iran was selected for the study area. To do the research, the Wu model (WM) was used and data related to the distribution and tensile strength of Oriental beech roots were collected. Root distribution was assessed using the concept of the root area ratio and trenching method. Laboratory tensile tests were conducted on fresh roots for strength characteristics. The factor of safety was calculated for two different soil thicknesses (1 and 2 m) and slope gradients between 10 and 45&deg;. The results showed that the root distribution generally decreased with increasing soil depth and the mean root strength value was 38.23 &plusmn; 1.19 MPa for 0.35&ndash;5.60 mm diameter range. The results verified a power relationship between tensile strength and root diameter. The reinforcement effect (C<sub>r</sub>) decreased with depth and the strongest reinforcement effect was in the second soil layer (10&ndash;20 cm) which showed a shear strength increase of 1.47 kPa. The increased factor of safety due to the presence of roots in one- and two-metre soil thicknesses was 27&ndash;44% and 15&ndash;26%, respectively. The improvement effect of roots was increased with increasing slope gradient and shallower soil thicknesses. &nbsp; &nbsp;

Plant Root Reinforcement Effect for Coastal Slope Stability

2015 ◽  
Vol 73 ◽  
pp. 216-219
Author(s):  
Yu Wang ◽  
Zongying Shu ◽  
Yingren Zheng ◽  
Shengxie Xiao
Keyword(s):  
Slope Stability ◽  
Plant Root ◽  
Reinforcement Effect ◽  
Root Reinforcement ◽  
Coastal Slope

scholarly journals Minimum representative root distribution sampling for calculating slope stability in Pinus radiata D.Don plantations in New Zealand

2020 ◽  
Vol 50 ◽  
Author(s):  
Filippo Giadrossich ◽  
Massimiliano Schwarz ◽  
Michael Marden ◽  
Roberto Marrosu ◽  
Chris Phillips
Keyword(s):  
Water Quality ◽  
New Zealand ◽  
Slope Stability ◽  
Pinus Radiata ◽  
Root Distribution ◽  
Soil Loss ◽  
Mean Value ◽  
Management Tools ◽  
Root Reinforcement ◽  
Characteristic Value

Background: Rainfall-triggered shallow landslides on steep slopes cause significant soil loss and can be hazards for property and people in many parts of the world. In New Zealand’s hill country, they are the dominant erosion process and are responsible for soil loss and subsequent impacts on regional water quality. Use of wide-spaced trees and afforestation with fast growing conifers are the primary land management tools in New Zealand to help control erosion and improve water quality. To decide where to implement erosion controls in the landscape requires determining the most susceptible places to these processes and models that incorporate how trees reinforce soils to understand if, and when, such treatments become effective. Methods: This paper characterises the mechanical properties of Pinus radiata D.Don roots (the common tree species used for afforestation in New Zealand) by means of field pullout tests and by measuring the root distribution at 360 degrees around trees. The Root Bundle Model (RBM) was used to calculate the root reinforcement. Statistical analysis was carried out to assess the statistical reduction coefficients of root reinforcement that depend on the number of measurements, used in geotechnical analysis to reduce the mean value of a parameter to a so-called characteristic value. Results: We show that to reach an effective level of root reinforcement, trees of 0.5 m DBH require a density of about 300 trees per hectare. Trees of this size are about 30 years of age across many sites and have generally reached the recommended conditions for clear-fell harvesting. The analysis of variance shows that 4 trees are the minimum number to be excavated to obtain sufficient root information to obtain less than 5% of error with a 95% of probability on the estimation of a design value of root reinforcement in accord with geotechnical standards. Conclusions: We found that the variability of lateral and basal root reinforcement does not limit the implementation of vegetation in slope stability models for Pinus radiata. We adopt for the first time the concept of a minimum sampling requirement and characteristic value, similarly to what is assumed for the value of effective soil cohesion in geotechnical guidelines for slope stability calculations.

A new tool to accurately calculate root reinforcement: the Root Bundle Model software RBM++

2020 ◽  
Author(s):  
Ilenia Murgia ◽  
Denis Cohen ◽  
Filippo Giadrossich ◽  
Gian Franco Capra ◽  
Massimiliano Schwarz
Keyword(s):  
Slope Stability ◽  
Tree Species ◽  
Root Distribution ◽  
Mechanical Characteristics ◽  
Model Complexity ◽  
Small Scale ◽  
Soil System ◽  
Root Reinforcement ◽  
Essential Information ◽  
Pullout Tests

&lt;p&gt;The influence of vegetation on the hydro-geomorphological response is widely recognized, and root reinforcement mechanisms are an important component of slope stability models. The calculation of this essential information is very complex because of the multiple interactions in the root-soil system, but also because of several mechanical characteristics that influence the tension and compression behaviour of the root itself.&lt;/p&gt;&lt;p&gt;This contribution has two aims. The first one is to show parameters of root reinforcement effects of Robinia pseudoacacia (L.), a tree commonly used for the mitigation of rainfall-induced landslides at small scale. This species is very widespread because it is able to grow on marginal areas, such as abandoned hillside sites, or on infrastructures, such as road and railway scarps, but its characterization represents a gap in knowledge in the literature. Field pullout tests were performed to collect input data for the quantification of root reinforcement using the Root Bundle Model with Weibull survival function (RBMw, Schwarz et al, 2013). Recent studies have shown how the RBMw is a very efficient model for the evaluation of root reinforcement by considering the heterogeneity of both root mechanical characteristics and their distribution in the soil. However, due to the model complexity and the need for information difficult to obtain, other simpler but less accurate approaches, such as the Wu model, have been preferred.&amp;#160;&lt;/p&gt;&lt;p&gt;For this reason, the second aim of the work is to present a new tool written in C++, and called RBM++, easy to use that enables anyone, from Universities to private companies, to quantify the effect of roots on slope stability. RBM++ allows the calculation of root reinforcement using two different methods: the first one by entering own data of the mechanical parameters of the roots, estimated beforehand with pullout tests in the field, and the root distribution in the soil; the second one by selecting the tree species and the data related to the spatial root distribution. For the first method, it is necessary to use a pullout machine to obtain the data. Because this instrument is not commonly available the model has the option to use default parameters for nine tree species based on values found in the literature.&amp;#160;&lt;/p&gt;&lt;p&gt;Output from RBM++ comes in tabular format and with a plot that shows, via the graphical user interface, the spatial distribution of forces as a function of the distance from the tree trunk and size of the tree.&amp;#160;&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;RBM++ makes it easier to share and exchange knowledge related to root reinforcement. Therefore, it will allow the realization of a database containing standard data on root mechanical behavior of tree species commonly used for shallow landslide mitigation.&lt;/p&gt;

scholarly journals Root Reinforcement Effect on Cover Slopes of Solid Waste Landfill in Soil Bioengineering

2021 ◽  
Vol 13 (7) ◽  
pp. 3991
Author(s):  
Jeongjun Park ◽  
Indae Kim ◽  
Jeong-Ku Kang
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Solid Waste ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Reinforcement Effect ◽  
Root Reinforcement ◽  
The Stability ◽  
Solid Waste Landfills

This study investigated the effect of vegetation plant roots on the stability of the cover slopes of solid waste landfills. A large direct shear test and a root tensile strength test were conducted to quantify the effect of rooted soil of revegetation plants on the increment in shear strength of the soil as a method to protect the cover slope of solid waste landfills. In the large direct shear test, an increase in the shear strength of the ground with the presence of roots was observed, and the root reinforcement proposed in the literature was modified and proposed by analyzing the correlation between the root diameter and the tensile strength according to water content. The stability of the slope revegetation of a landfill facility, considering the root reinforcement effect of revegetation, was calculated by conducting a slope stability analysis reflecting the unsaturated seepage analysis of rainfall conditions for various analysis conditions, such as the gradient, the degree of compactness, the thickness of the cover, and the rooted soil depth of the landfill facility.

scholarly journals Modeling root reinforcement using a root-failure Weibull survival function

2013 ◽  
Vol 17 (11) ◽  
pp. 4367-4377 ◽  
Author(s):  
M. Schwarz ◽  
F. Giadrossich ◽  
D. Cohen
Keyword(s):  
Mechanical Properties ◽  
Slope Stability ◽  
Root Distribution ◽  
Survival Function ◽  
Root Diameter ◽  
Root Turnover ◽  
Diameter Class ◽  
Root Reinforcement ◽  
Root Strength ◽  
Steep Slopes

Abstract. Root networks contribute to slope stability through complex interactions with soil that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamics of root turnover, the quantification of root reinforcement on steep slopes is challenging and consequently the calculation of slope stability also. Although considerable progress has been made, some important aspects of root mechanics remain neglected. In this study we address specifically the role of root-strength variability on the mechanical behavior of a root bundle. Many factors contribute to the variability of root mechanical properties even within a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field data sets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the equations of the tensile force, the elasticity of the roots, and the root distribution are the most important steps. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows for the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

scholarly journals Modeling root reinforcement using root-failure Weibull survival function

2013 ◽  
Vol 10 (3) ◽  
pp. 3843-3868 ◽  
Author(s):  
M. Schwarz ◽  
F. Giadrossich ◽  
D. Cohen
Keyword(s):  
Mechanical Properties ◽  
Slope Stability ◽  
Root Distribution ◽  
Survival Function ◽  
Root Diameter ◽  
Root Turnover ◽  
Diameter Class ◽  
Stability Calculation ◽  
Root Reinforcement ◽  
Root Strength

Abstract. Root networks contribute to slope stability through complicated interactions that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamic of root turnover, the quantification of root reinforcement on steep slope is challenging and consequently the calculation of slope stability as well. Although the considerable advances in root reinforcement modeling, some important aspect remain neglected. In this study we address in particular to the role of root strength variability on the mechanical behaviors of a root bundle. Many factors may contribute to the variability of root mechanical properties even considering a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field datasets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the tensile force and the elasticity of the roots are the most important equations, as well as the root distribution. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

scholarly journals Stability Analysis of Plant-Root-Reinforced Shallow Slopes along Mountainous Road Corridors Based on Numerical Modeling

Geosciences ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Damtew Tsige ◽  
Sanjaya Senadheera ◽  
Ayalew Talema
Keyword(s):  
Tensile Strength ◽  
Stability Analysis ◽  
Slope Stability ◽  
Plant Species ◽  
Factor Of Safety ◽  
Triaxial Compression ◽  
Slope Angle ◽  
Plant Roots ◽  
Soil Parameters ◽  
Slope Stabilization

Engineering methods such as soil nails, geosynthetic reinforcement, retaining structures, gabions, and shotcrete are implemented to stabilize road cut slopes along mountainous areas. However, these structures are not environmentally friendly and, particularly in Ethiopia, it is impossible to address all road problems due to financial limitations. Nowadays, soil reinforcement with plant roots is recognized as an environmentally sustainable alternative to improve shallow slope failure along mountainous transportation corridors. The aims of this study was, therefore, to conduct slope stability analysis along a road corridor by incorporating the effect of plant roots. Five plant species were selected for the analysis based on their mechanical characteristics. Namely, Eucalyptus globules (tree), Psidium guajava (shrub), Salix subserrata (shrub), Chrysopogon zizanioides, and Pennisetum macrourum (grasses). The roots’ tensile strength and soil parameters were determined through tensile strength testing and triaxial compression tests, respectively. The factor of safety of the slope was calculated by the PLAXIS-2D software. The study showed that when the slope was reinforced with plant roots, the factor of safety (FOS) improved from 22–34%. The decreasing effect of vegetation on slope stability was observed when soil moisture increased. The sensitivity analysis also indicated that: (1) as the spacing between plants decreased, the effect of vegetation on the slope increased. (2) Slope angle modification with a combination of plant roots had a significant impact on slope stabilization. Of the five-selected plant species, Salix subserrata was the promising plant species for slope stabilization as it exhibited better root mechanical properties among selected plant species.

The Use of Controlled Dissolution Glasses to Consolidate and Create Permeable or Impermeable Minerals in Formation

2021 ◽  
Author(s):  
Max Olsen ◽  
Ragni Hatlebakk ◽  
Chris Holcroft ◽  
Arne Stavland ◽  
Nils Harald Giske ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Oil And Gas ◽  
Stable Solution ◽  
Oil And Gas Industry ◽  
Post Treatment ◽  
Strength Increase ◽  
Glass Technology ◽  
Nuclear Waste Storage ◽  
Wide Range ◽  
Glass Compositions

Abstract Scope Controlled dissolution glasses form a permanent consolidating mineral matrix inside formations with either permeable or impermeable properties. The unique solution has a low injection viscosity and can be easily injected into a wide range of formations. The application method is simple and does not require multiple fluids or pre- and post-flushing. This paper focuses on the benefits of controlled dissolution glasses and potential applications in the oil and gas industry. Methods, Procedures, Process Controlled dissolution glasses have been researched extensively by Glass Technology Services (GTS) since 1999 for the biomedical industry, nuclear waste storage industry, and defense and aerospace industries. GTS together with operators have been performing research and development for the oil industry over the last 10 years. The research investigated different glass compositions to determine their injectability and change in formation properties post-treatment. Sandstone, chalk, and shale formations were used in the testing. Flow testing using a Hoek cell and a core flood apparatus was used to determine the post-treatment permeability. For post-treatment strength measurement, Brazilian tensile strength tests and modified cone penetration tests were used to determine tensile strength and shear strength respectively. The testing evaluated different mixing fluids, such as water and different brines, compatibility, corrosion testing, and concentrations. Results, Observations, Conclusions The testing identified different glass compositions and concentrations that are suitable for different applications and formations. Certain glass compositions increase tensile strength significantly while also maintaining the permeability in the formation. Other glass compositions have similar tensile strength increase, but result in an impermeable seal. The liquid glass solutions react with the formation to form a mineral precipitation inside the formation. The reaction with the formation occurs quickly at downhole conditions, within hours of placement. The glass can be mixed with water and variety of brines to form a stable solution across a range of densities. The testing and results to date have laid the foundation for use in a variety of consolidation and P&A applications in oil and gas wells. Testing is ongoing for a chalk and sandstone consolidation solution and for a sealing solution. Novel/Additive Information These novel glass solutions can solve many of the production and instability challenges that plague weak formations. The glasses can be injected into very low permeability formation to either seal or consolidate.

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