scholarly journals A Determination Method of Rainfall Type Based on Rainfall-Induced Slope Instability

2021 ◽  
Author(s):  
Yafen ZHANG ◽  
Yulong ZHU ◽  
Xiaoyu YAN ◽  
Shu LI ◽  
Qijing YU ◽  
...  
Keyword(s):  
Shear Strength ◽  
Slope Failure ◽  
Slope Instability ◽  
Determination Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Failure Initiation ◽  
Soil Shear Strength ◽  
Rainfall Type

Abstract This work presents a determination method of rainfall types based on rainfall-induced slope instability to eliminate the current dilemma of the inconsistent classification of rainfall types. Firstly, 5,808 scenarios of slope instability are simulated with 11 kinds of soil properties under 528 designed intensity-duration (I−D) conditions. Then through analysis of the I−D conditions when slope failure occurred, rainfall is classified into two types: short-duration − high-intensity (SH) type, and long-duration − low-intensity (LL) type. According to the analysis results, it indicates that rainfall types affect the initiation of slope failure, i.e., different I−D conditions will affect the slope failure initiation under LL type rainfall, while the slope failure initiation will not be affected by the change of I−D conditions under SH type rainfall. In addition, the results show that the classification of rainfall types does not depend on the soil shear strength parameters (cohesion and internal friction angle), although the change of soil shear strength parameters will cause the shift of threshold curve of slope failure in the I−D conditions two-dimensional (2D) plane. The findings in this study benefit to understanding the effect of rainfall type on the mechanism of slope failure initiation, which will promote the development of an early warning system of slope failure in the future by considering the identification of rainfall types.

scholarly journals Application of geotextile ropes in slope erosion protection

2018 ◽  
Vol 196 ◽  
pp. 03023
Author(s):  
Giang Nguyen ◽  
Jan Broda ◽  
Joanna Grzybowska-Pietras
Keyword(s):  
Shear Strength ◽  
Slope Failure ◽  
Shear Strength Parameters ◽  
Slope Surface ◽  
Strength Parameters ◽  
Slope Inclination ◽  
Gravel Pit ◽  
Hydraulic Conditions ◽  
Soil Shear Strength ◽  
Erosion Protection

Paper deals with application of geotextile ropes in erosion protection of slope of gravel pit in Nieboczowy, Poland. For protection of the slope the segments formed from thick ropes were applied. The ropes with the diameter of 120 mm were produced by the Kemafil technology. Ropes were made from strips of stitch-bonded nonwoven produced from a mixture of recycled natural and synthetic fibres and strips of wool needle-punched nonwoven. The protected slope had the length of 4 to 6 m, slope inclination from 1:1 to 1:1.8 and total area of approximately 150 m2. It will be shown that installed ropes restrain soil so there is no slope failure in protected section even in case of low soil shear strength parameters and unfavourable hydraulic conditions. Generally slope surface in protected section is without rills and gullies. This case also shows that plants are very good anti-erosion measure. Thanks ropes installed on the slope, favourable conditions for plants growth are created and maintained.

scholarly journals Mechanical Behaviour of Reinforced Sand with Natural Curauá Fibers through Full Scale Direct Shear Tests

2019 ◽  
Vol 92 ◽  
pp. 12003
Author(s):  
Leila Maria Coelho de Carvalho ◽  
Michelé Dal Toé Casagrande
Keyword(s):  
Shear Strength ◽  
Sandy Soil ◽  
Soil Reinforcement ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Shear Tests ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Soil Shear Strength ◽  
Curaua Fibers

Inclusion of natural fibers (sisal, curauá, coco fiber and others) for soil improvement has been the study object in diverse geotechnical areas and it is a topic of growing interest, within the research area of new geotechnical materials. The state of the art in this subject highlights excellent results as soil strength parameters improve and post-cracking strength (toughness) increase. Soil reinforcement technique with fibers is established in the technology of composite materials, this being a combination of two or more materials presenting properties that the component materials do not possess on their own. The aim of this paper is to study the mechanical behaviour of sand-fiber composite by inserting natural curauá fibers into a sandy matrix, with different fiber contents. The fibers were randomly distributed in the soil mass. The experimental program included physical and mechanical characterization of the composites, using full-scale direct shear tests, with samples measuring 30 x 30 cm and 15 cm high. Direct shear tests were carried out using fibers with 25 mm length and 0.5 and 0.75% fiber content (relative to the soil dry weight). The specimens also presented a relative density of 50% and moisture content of 10%. It was sought to establish a pattern behaviour so that the addition of curauá fiber influence can be explained, thus, comparing with the sandy soil shear strength parameters. Inclusion of natural curauá fibers as soil reinforcement presented satisfactory results, as an increase in the soil shear strength parameters was observed when compared with sandy soil results.

scholarly journals Application of Innovative Ropes from Textile Waste as an Anti-Erosion Measure

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1179
Author(s):  
Giang Nguyen ◽  
Joanna Grzybowska-Pietras ◽  
Jan Broda
Keyword(s):  
Shear Strength ◽  
Physical And Mechanical Properties ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Synthetic Fibers ◽  
Direct Shear Tests ◽  
Hydraulic Conditions ◽  
Soil Shear Strength ◽  
Erosion Protection ◽  
Recycled Material

Using materials from recycling is a key part of decreasing present-day waste. It is optimal for recycled material to be used in environmental protection. This paper presents the application of geotextile ropes in erosion protection of a slope of a gravel pit. To protect the slope, thick ropes with a diameter of 120 mm made from wool and a mixture of recycled natural and synthetic fibers were used. After 47 months from installation, soil and rope specimens were taken from the slope parts with inclinations 1:1 and 1:1.8, and their physical and mechanical properties were determined. Direct shear tests were applied to determine the soil shear strength parameters in state at sampling and at Ic = 0 (unconsolidated and consolidated). Based on the obtained soil shear strength parameters, the loads on the ropes were determined, taking into account also unfavorable hydraulic conditions and compared to rope strength. It was shown that even after 47 months from installation, rope tension strength was higher as tension forces were induced in the ropes in every case. At present, whole slopes in protected sections are stabilized, without rills and gullies.

Uncertainties of Shear Strength Parameters of Soil Reinforced by Plastic Waste

2015 ◽  
Vol 744-746 ◽  
pp. 695-701
Author(s):  
Giang Nguyen ◽  
Eva Hrubesova ◽  
Jan Maršálek ◽  
Tomáš Petřík ◽  
Marek Mohyla
Keyword(s):  
Shear Strength ◽  
Polyethylene Terephthalate ◽  
Laboratory Tests ◽  
Ground Improvement ◽  
Overwhelming Majority ◽  
Waste Materials ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Soil Shear Strength

In geotechnical practice we often meet the case when soils need to be improved. Various methods for the ground improvement are used in the geotechnical practise. One from methods of soils improvements can use also fiber-shaped waste materials. Such as polyethylene terephthalate (PET) plastic bottles are profusely and widely produced, yet used little for engineering purpose, and the overwhelming majority of them are placed in storage or disposal sites.One form expected improvements is increase of soil shear strength parameters which can be obtained by various methods, including laboratory tests. Determination of soil shear strength parameters by DST is still extensively used. In this paper we will deal with soil shear strength parameters of soil without and with plastic chips and their uncertainty. Uncertainties of shear strength parameters of soil without or with plastic chips are not negligible.

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