Relationship Between Near Seafloor Seismic Amplitude, Impedance, and Soil Shear Strength PropertIes and Use in Prediction of Shallow Seated Slope Failure

Author(s):  
J. R. Brand ◽  
D. L. Lanier ◽  
W. J. Berger ◽  
V. R. Kasch ◽  
A. G. Young
2019 ◽  
Vol 24 (2) ◽  
pp. 113
Author(s):  
Paravita Sri Wulandari ◽  
Daniel Tjandra

Reservoir is needed as a source of water supply to the surrounding populations. The design of a reservoir needs to consider several aspects of soil embankment such as variations in water content and changes in shear soil shear strength and also the influence of water level in reservoir. The purpose of this research is to analyze these three aspects in the design of a reservoir. This research was begun by taking soil samples for embankment and conducting soil tests to obtain soil characteristics at the initial condition. The further laboratory tests were conducted to determine the effect of changes in water content on the shear strength of the soil. The variation of soil embankment characteristic was then modeled by Plaxis 2D program to obtain the effect of changes in soil embankment characteristic and fluctuation of the water level in the reservoir. The results showed that the increase in water content significantly decrease the shear strength of the soil. The changes of soil shear strength affect the pattern of slope failure and safety factor. In addition, the pattern and direction of the slope failure were also influenced by the water level of the reservoir.


2021 ◽  
Vol 42 (3(SI)) ◽  
pp. 857-864
Author(s):  
Z.A. Rahman ◽  
◽  
A.E. Ettbeb ◽  
W.M.R. Idris ◽  
S.N.A. Tarmidzi ◽  
...  

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.


Author(s):  
Hestin Mulyandari ◽  
Adwiyah Asyifa

ABSTRACTCode riverbanks are dominated by land for settlements, one of the points being the proposed establishment of rusunami, in Jetisharjo, city of Yogyakarta. Riverbanks at the location are slippery, so have many problems of structure and infrastructure. In the planning of rusunami, it is necessary to consider the location of the communal septic tank. The research use method of quantitative research. The results of soil testing are soil moisture content of 7.788%, density of 2.688, soil shear strength (Ʈ) of 0.870 kg/cm2, internal friction angle of 440, and sandy soil. The results of the shear strength testing of the land that the selected location contain subgrade, so that if it will be used as a communal septictank, it needs to be made a strong enough foundation to avoid degradation and slope failure, the construction of communal septic tanks must be made strong so that they can avoid lift by water pressure.Keywords: soil test, communal septic tank, contoured land ABSTRAKBantaran Sungai Code  didominasi lahannya untuk permukiman, salah satu titiknya menjadi usulan berdirinya rusunami, di RW 07 Kecamatan Jetisharjo, Kota Yogyakarta. Bantaran Sungai di lokasi tersebut sangat curam, sehingga dari segi struktur dan infrastruktur banyak mengalami kendala. Pada perencanaan rusunami nantinya perlu diperhitungkan titik-titik yang menjadi lokasi septic tank komunalnya. Metode penelitian yang digunakan adalah penelitian kuantitatif. Hasil pengujian tanah sebagai berikut: kadar air tanah sebesar 7, 788%, berat jenis sebesar 2,688, kuat geser tanah (Ʈ) sebesar 0,870 kg/cm2, sudut gesek internalnya  440, dan berjenis tanah pasir. Dari hasil uji gesernya kekuatan tanahnya bahwa lokasi terpilih merupakan bekas tanah urug, sehingga apabila akan dijadikan septictank komunal perlu dibuatkan fondasi yang cukup kuat untuk menghindari  penurunan dan kelongsoran tebing, maka konstruksi septic tank komunal harus dibuat kokoh sehingga dapat terhindar dari up lift oleh tekanan air.Disarankan menggunakan septic tank moderen (fabricated).Kata kunci: uji tanah, septic tank komunal, lahan berkontur


2020 ◽  
Vol 27 (1) ◽  
pp. 48-54
Author(s):  
Hong Yau Wong

With the recent advancement in technology, the method, accuracy and speed of slope stability analysis have been vastly improved. Nevertheless, the reliability and appropriateness of such analysis can be very much in doubt if the soil behaviour, in particular the shear strength behaviour, is not fully understood. The objective of this paper is therefore to evaluate the shear strength behaviour of various soil types in Hong Kong. This comprises the collection, processing and analysis of the laboratory and field works carried out in the past few decades, in particular the triaxial compression testing in the laboratory and standard penetration test (SPT) in the field. For correlating SPT with soil shear strength, a fairly large number of carefully controlled site investigation works with SPT are carried out both above and below any Mazier sampling. Laboratory triaxial tests are then carried out in these Mazier samples. Finally, it is hoped that a basically quantitative relationship between soil shear strength and SPT can be obtained as this would enable a soil shear strength profile to be established once the corresponding SPT profile has been determined on site by carrying out SPT in adequate number of drill holes.


2018 ◽  
Vol 196 ◽  
pp. 03023
Author(s):  
Giang Nguyen ◽  
Jan Broda ◽  
Joanna Grzybowska-Pietras

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.


2021 ◽  
Author(s):  
Yafen ZHANG ◽  
Yulong ZHU ◽  
Xiaoyu YAN ◽  
Shu LI ◽  
Qijing YU ◽  
...  

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.


UKaRsT ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 163
Author(s):  
Dyah Wahyu Apriani ◽  
Umar Mustofa ◽  
Rachmad Hidayat

Slope failure is a complex event. It can provide useful information about the condition of soil parameters on the failed slope in the same way it can provide an opportunity to evaluate the stability of other slopes. To evaluate the occurence of slope failure, unit weight data and shear strength properties of soil are needed, as well as methods of analysis including failure mechanisms. One of the methods used to evaluate landslide events is reverse analysis. In this study, reverse analysis was carried out on landslides that occurred on the slopes of D-D 'and F-F' at the Integrated Campus Building of the Institut Teknologi Kalimantan. The finite element method is used to analyze the safety number of the slopes under review. From the results of the reverse analysis, it was obtained that the soil parameters at the time of collapse in the top layer resulted in the value of unit weight (γ) = 20 kN / m2, Cohesion (c) = 2 kPa and Internal friction angle (φ) = 27 ° . Slope failure occured due to an increase in soil volume weight value, as well as a decrease in soil shear strength parameters, namely cohesion and internal friction angle.


2016 ◽  
Vol 78 (8-5) ◽  
Author(s):  
Nyimas Septi Rika Putri ◽  
Ratna Dewi ◽  
Muhammad Ilham

Soft soil possess poor mechanical properties, thus produce problems when bearing load. To overcome the problems, soft soil has to be stabilised. To do soil stabilisation, it Is imperative to add some mixture as additional substance in order to improve the characteristic of the soft soil. Plastic sacks fibre is one of the easily obtainable material which consists of high density profile, while bran ash contains good carbon and silica. This research aimed to determine the optimum level of plastic sacks waste fibre and bran ash to obtain the maximum soil shear strength and to compare the original soil shear strength with the modified mixture soil shear strength. The strength tests were conducted on the laboratory scale using the triaxial test device for the Unconsolidated Undrained (UU) test. Soft clay sample was mixed with the chop of plastic sacks fibre with the following level of composition : 0.4 % , 0.6 %, 0.8 %, 1 %, and also the bran ash composition content of  0 %, 2 % and 4 % to the dry weight of soil with the test unit of 36 pieces. Based on laboratory testing, the maximum cohesion value reside on variation of 0.8 % plastic sacks fibre and 2 % bran ash with the value of 0.65 kg/cm2, and the maximum shear angle lays on variation of 1 % of plastic sacks fibre and 0 % of bran ash with the value of 9.95 degree. For the mixture variation of 0.8 % plastic sacks fibre and 2 % of bran ash, it produced a shear strength of 0.67 kg/cm2 and abled to increase the soil shear strength by 87.08 %. As a conclusion, the use of plastic sacks fibre and bran ash was found to be able to improve the soft clay shear strength properties.


2021 ◽  
Vol 13 (15) ◽  
pp. 8164
Author(s):  
Brian E. Bautista ◽  
Lessandro E. O. Garciano ◽  
Luis F. Lopez

There are limited published studies related to the mechanical properties of bamboo species in the Philippines. In this study, the shear strength properties of some economically viable bamboo species in the Philippines were properly characterized based on 220 shear test results. The rationales of selecting this mechanical property are the following: (1) Shear strength, parallel to the fiber, has the highest variability among the mechanical properties; and (2) Shear is one of the governing forces on joint connections, and such connections are the points of failure on bamboo structures when subjected to extreme loading conditions. ISO 22157-1 (2017) test protocol for shear was used for all tests. The results showed that Bambusa blumeana has the highest average shear strength, followed by Gigantochloa apus, Dendrocalamus asper, Bambusa philippinensis, and Bambusa vulgaris. However, comparative analysis, using One-way ANOVA, showed that shear strength values among these bamboo species have significant differences statistically. A linear regression model is also established to estimate the shear strength of bamboo from the physical properties. Characteristic shear strength is also determined using ISO 12122-1 (2014) for future design reference.


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