scholarly journals Model Test of the Reinforcement of Surface Soil by Plant Roots under the Influence of Precipitation

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hengxing Wang ◽  
Yulong He ◽  
Zufeng Shang ◽  
Chunpeng Han ◽  
Yilu Wang
Keyword(s):  
Water Content ◽  
Model Test ◽  
Surface Soil ◽  
Plant Root ◽  
Root Systems ◽  
Reinforced Soil ◽  
Plant Roots ◽  
Interfacial Friction ◽  
Negative Power ◽  
Pull Out

We present the results of the reinforcement of plant root systems in surface soil in a model test to simulate actual precipitation conditions. In the test, Eleusine indica was selected as herbage to reinforce the soil. Based on the various moisture contents of plant roots in a pull-out test, a fitting formula describing the interfacial friction strength between the roots and soil and soil moisture content was obtained to explain the amount of slippage of the side slope during the process of rainfall. The experimental results showed that the root systems of plants successfully reinforced soil and stabilized the water content in the surface soil of a slope and that the occurrence time of landslides was delayed significantly in the grass-planting slope model. After the simulated rainfall started, the reinforcement effect of the plant roots changed. As the rainfall increased, the interfacial friction between the roots and the soil exhibited a negative power function relationship with the water content. These conclusions can be used as a reference for the design of plant slope protection and reinforcement.

scholarly journals Research on the Strength Variation of Root-Clay Systems under Freeze-Thaw Action

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Lin Yang ◽  
Hengxing Wang ◽  
Chunpeng Han ◽  
Hong Guo ◽  
Yafeng Gong ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Root System ◽  
Unconfined Compressive Strength ◽  
Reinforced Soil ◽  
Interfacial Friction ◽  
Setaria Viridis ◽  
Zoysia Japonica ◽  
Soil System ◽  
Freeze Thaw ◽  
Pull Out

The aim of this paper is to study the influence of an effective root system of rhizome plants on the reinforcement of slope soil under freeze-thaw conditions. This study focused on the mechanical properties between roots and clay in the root system of four plant species from different regions of China (northeast, northern, central, and southern areas): Setaria viridis, Eleusine indica, Zoysia japonica, and Carex leucochlora. Based on the interfacial friction effects between the plant roots and the soil, pull-out tests and unconfined compressive strength tests were conducted on the reinforced soil system for varying numbers of freeze-thaw cycles. Several stages of the pull-out process of the root system in clay are explicitly proposed based on the interfacial friction test results. The results showed that the friction effect between Zoysia japonica roots and the soil was the most significant and that these roots had the best reinforcement effect. In contrast, the friction and reinforcement effects between Setaria viridis roots and the soil were the worst, and the resulting unconfined compressive strength was the smallest. However, the freeze-thaw resistance ability of the Setaria viridis and soil system was stronger than that of the Zoysia japonica system.

scholarly journals Experimental Study on Mechanical Properties of Reinforced Soil Interface under Dry-Wet Cycle

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Liang Huang ◽  
Wenbo Ma ◽  
Yujie Hou ◽  
Bo Wang ◽  
Jiahua Zhu
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Working Conditions ◽  
Retaining Wall ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Overburden Pressure ◽  
Pull Out ◽  
Apparent Cohesion ◽  
Soil Interface

The reinforced soil-retaining wall has been widely used in coastal projects, and the dry-wet cycles influence the mechanical properties of the reinforced soil interface. This study conducts macro-micro tests and selects four different water content samples of reinforced soil with five types of overburden pressure conditions and three sets of dry-wet cycles, with a total of 60 working conditions. The pull-out test was used to study the mechanical properties of the reinforced soil interface. The scanning electron microscope was used to observe the microscopic characterization of the particles under different working conditions. Through the analysis of the experimental results, we can draw the conclusion as follows. (1) The friction coefficient of the reinforced soil interface decreases with the increase of the number of dry and wet cycles. (2) The apparent cohesion of soil-reinforcement interface decreases with the increase of the number of dry-wet cycles. After 30 dry-wet cycles, the apparent cohesion of the soil-reinforcement interface with water content of 14% is the maximum 5.91 kPa. The variation law of cohesion derived from microstructure analysis conforms to the laws and conclusions obtained by the experiment. (3) The shear stress of the reinforced soil is linearly related to the normal stress, which is in accordance with Coulomb’s law.

The role of soil resistance in determining water uptake by plant root systems

Soil Research ◽  
1983 ◽  
Vol 21 (4) ◽  
pp. 571 ◽  
Author(s):  
NR Hulugalle ◽  
ST Willatt
Keyword(s):  
Water Stress ◽  
Hydraulic Conductivity ◽  
Water Uptake ◽  
Plant Root ◽  
Soil Water Potential ◽  
Root Systems ◽  
Plant Roots ◽  
Soil Resistance ◽  
Plant Root Systems

Resistance to water flow in plant roots has been suggested as a significant factor limiting water uptake by plants. The results of previous experiments have been used to show that soil resistance may be more significant than has recently been suggested, particularly in soils of low hydraulic conductivity and where root density is low. As the technique used to determine soil resistance relies on hydraulic conductivity, the latter may be more appropriate as an indicator of water stress than soil water potential.

scholarly journals The mechanism of the plant roots’ soil-reinforcement based on generalized equivalent confining pressure

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10064
Author(s):  
Ping Guo ◽  
Zhenyao Xia ◽  
Qi Liu ◽  
Hai Xiao ◽  
Feng Gao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Root Distribution ◽  
Plant Root ◽  
Friction Angle ◽  
Confining Pressure ◽  
Distribution Patterns ◽  
Reinforced Soil ◽  
Soil Reinforcement ◽  
Plant Roots ◽  
Root Content

Background To quantitatively evaluate the contribution of plant roots to soil shear strength, the generalized equivalent confining pressure (GECP), which is the difference in confining pressure between the reinforced and un-reinforced soil specimens at the same shear strength, was proposed and considered in terms of the function of plant roots in soil reinforcement. Methods In this paper, silt loam soil was selected as the test soil, and the roots of Indigofera amblyantha were chosen as the reinforcing material. Different drainage conditions (consolidation drained (CD), consolidation undrained (CU), and unconsolidated undrained (UU)) were used to analyse the influences of different root distribution patterns (horizontal root (HR), vertical root (VR), and complex root (CR)) and root contents (0.25%, 0.50%, and 0.75%) on the shear strength of soil-root composites. Results The cohesion (c) values of the soil-root composites varied under different drainage conditions and root contents, while the internal friction angle (φ ) values remain basically stable under different drainage conditions. Under the same root content and drainage conditions, the shear strength indexes ranked in order of lower to higher were HR, VR and CR. The GECP of the soil-root composites with a 0.75% root content was 1.5–2.0 times that with a 0.50% root content and more than 5 times that with a 0.25% root content under the CD and CU conditions. The GECP in reinforced soil followed the sequence of CD > CU > UU. The GECP of the plant roots increased as confining pressure increased under CD and CU conditions while showed a complex change to the confining pressure under the UU condition. Conclusion It was concluded that the evaluation of plant root reinforcing soil based on GECP can be used to measure effectively the influences of roots on soil under different drainage conditions and root distribution patterns.

Using soil surface gray level to determine surface soil water content

2010 ◽  
Vol 53 (10) ◽  
pp. 1527-1532 ◽  
Author(s):  
YuanJun Zhu ◽  
YunQiang Wang ◽  
MingAn Shao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Surface Soil ◽  
Soil Surface ◽  
Gray Level

Evaluating Surface-Soil Water Content by Measuring Reflectance

1975 ◽  
Vol 39 (2) ◽  
pp. 238-242 ◽  
Author(s):  
E. L. Skidmore ◽  
J. D. Dickerson ◽  
H. Schimmelpfennig
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Surface Soil

scholarly journals OPTIMALISASI PRODUKSI ENZIM KITINASE PADA ISOLAT JAMUR KITINOLITIK DARI SAMPEL TANAH RIZOSFER

2018 ◽  
Vol 3 (01) ◽  
pp. 62-69
Author(s):  
Eka Corneliyawati ◽  
Massora Massora ◽  
Khikmah Khikmah ◽  
As’ad Syamsul Arifin
Keyword(s):  
Biological Control ◽  
Cell Wall ◽  
Rhizosphere Soil ◽  
Plant Root ◽  
Optimal Growth ◽  
Chitinase Activity ◽  
Fungal Species ◽  
Plant Roots ◽  
Chitinase Production

The rhizosphere is the zone of soil surrounding a plant root where plant roots, soil and the soil biota interact with each other. Chitinolytic fungi has been effectively used in biological control agens. The chitinase activity causes lysis of the fungi cell wall pathogen. The aim of the research was to find optimization of activity chitinase enzyme from rhizosphere soil was conducted in vitro. Optimal growth chitinase production for TKR3 fungi isolate were concentration of chitin 0,2% (b/v), pH 5,5, temperature 30ºC, agitation 150 rpm and incubation time at four days. The optimum yield of chitinase production is influenced by fungal species and environmental conditions.

scholarly journals Ground improvement using granular pile anchor system: resistance to heave and uplift pressure

2020 ◽  
Vol 19 (1) ◽  
pp. 403
Author(s):  
Alvin John Lim Meng Siang ◽  
Ehab Hamad Sfoog ◽  
Nahla Naji ◽  
Sim Sy Yi ◽  
Nickholas Anting Anak Guntor ◽  
...  
Keyword(s):  
Moisture Absorption ◽  
Expansive Soils ◽  
Ground Improvement ◽  
Reinforced Soil ◽  
Scale Model ◽  
Small Scale ◽  
Numerical Investigations ◽  
Anchor System ◽  
Pull Out ◽  
Granular Pile

<span lang="EN-GB">Expansive soil is found in many parts of the world where its major drawback is its expansion and shrinking property upon moisture absorption and drying during alternation of rainy-dry seasons. Due to its swelling-shrinkage repeated process, fatigue and distress cause crack to structures. Granular pile anchor (GPA) system is a pioneering technique that is utilised in reinforcing these expansive soils. Granular pile anchor (GPA) system is a pioneering technique that is utilised in reinforcing expansive soils. The GPA provides tensile resistance which arrest the exerted upward forces and hence reducing heave. Previous investigations have only focused on load-displacement relationships by utilizing the pull-out technique. In this technique, an external force pulls the GPA and the corresponding displacements are recorded. The results provide indication of the GPA resistance to the applied force. However, in real conditions the heave and expansion forces were developed as a result of the pressure caused by the water absorption which pushes the entire soil bed in the upward direction along with the GPA. Therefore, this paper is aimed to explore this concept by carrying experimental and numerical investigations on a small scale model for a single pile with a diameter of 4 cm, with lengths of 20 and 40 cm. Ultimately, the reinforced soil exhibits reduction in upward force and heave compared to the unreinforced soil. Also, verifications for the testing shows that the relationship between the upward force and heave exhibits almost linear relationship for both experimental and numerical investigations. Therefore, shallow foundations incorporated with a GPA system proves to effectively lessen the heave that occurs in expansive soils which in turn can solve problems for constructions.</span>

scholarly journals Model Test Research on the Influence of Gate Blocking in Siltation Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hua Li ◽  
Yifeng Wang ◽  
Jingyu Zhang ◽  
Liangpeng Wan ◽  
Qiao Jiang ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Model Test ◽  
Significant Influence ◽  
High Water ◽  
Deep Hole ◽  
Analysis Model ◽  
Pull Out ◽  
Test Study ◽  
Similarity Ratio ◽  
Pulling Force

Aiming at the clogging problems encountered in the operation of deep-hole gates in high water level reservoirs and dams, this paper carried out a model test study on the influence of different materials and different siltation environments on the lifting of the gates and analyzed the rules of the effects of blockages in different siltation environments. An analysis model of the pull-out force of the gate (blocked object) considering the siltation environment was proposed in an innovative way and the similarity ratio relationship was verified. The results of the study show that (1) the size and time of the siltation and other factors have a significant influence on the pulling force of the blocked object. It increases with the increase of the siltation area. The longer the siltation goes on, the greater the pulling force will be. (2) As the similarity ratio n increases, the calculation result of the analysis model is closer to the target value n 2 and it indicates that the theoretical model is reliable. The research results of this paper can provide certain guidance for deep-hole siltation dispatch to ensure project safety.

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