scholarly journals Deslizamento em Uma Vertente do Rio Madeira em Porto Velho – RO: Uma Análise Morfomecânica

2019 ◽  
Vol 12 (5) ◽  
pp. 1980
Author(s):  
Salem Leandro Moura dos Santos ◽  
Eliomar Pereira da Silva Filho ◽  
Isabel Leonor Iza Echeverria Herrera

Este estudo tem o objetivo de estabelecer o nível piezométrico que a vertente tinha antes do deslizamento, a morfometria e a causa do movimento de massa. Para isto, foi utilizada equação de Equilíbrio-Limite, com o Fator de segurança em 1,49 para estabelecer o nível piezométrico necessário para causar o colapso da encosta, como também, a determinação de propriedades geomecânicas, como coesão, densidade, ângulo de atrito, tensão de cisalhamento, limites de Atterberg, além da granulometria e da morfometria. A vertente apresentava o formato convexo no topo e côncavo na base, ambos seccionados no meio pelos formatos retilíneo e côncavo. A inclinação média era de 35,17° em uma dimensão de 46,01m. A Equação indicou um nível piezométrico mínimo de 18,53 metros de altura para o colapso. Um aspecto que influenciou o deslizamento foi à erosão superficial causada por uma galeria de água pluvial, que uma vez rompida, erodiu o pacote de material superficial, Argilo Siltoso Mosqueado, que serve de proteção para a vertente, pois possui maior coesão e plasticidade. Após a completa erosão do pacote superior, houve a exposição pontual do pacote inferior, que após sofrer forte precipitação pluvial de 32,20 mm, ocorrida no dia 30/09/2013, ocasionou a elevação do nível piezométrico deste material inferior, Silto Arenoso Tangencial, de menor coesão e plasticidade que saturou, comportando-se de maneira semi-líquida. Devido este material ser todo o alicerce da encosta, o seu colapso causou todo o deslizamento rotacional da vertente. Verifica-se a importância de manter o material superior desta margem do Rio  Landslide in The Madeira River Slope in Porto Velho - RO: A Morfomechanical analysis ABSTRACTThe aims this paper is establish the piezometric level that the slope had before sliding, morphometry and the cause of mass movement. For this, the Equilibrium-Limit equation was used, with the Safety Factor at 1.49 to establish the piezometric level necessary for collapse of the slope, as well as the determination of geomechanical properties, such as cohesion, density, friction angle , shear stress, Atterberg boundaries, granulometry and morphometry. The strand had the convex shape at the top and concave at the base, both sectioned in the middle by the rectilinear and concave shapes. The average slope was 35.17° in a dimension of 46.01m. Equation indicated a minimum piezometric level of18.53 metershigh for collapse. One aspect that influenced the sliding was the superficial erosion caused by a gallery of rainwater, which once ruptured, eroded the package of surface material, Silt Clay Mottled, which serves as protection for the slope, as it has greater cohesion and plasticity. After complete erosion of the upper package, there was a punctual exposition of the lower package, which after suffering heavy rainfall of32.20 mm, occurred on 09/30/2013, caused the elevation of the piezometric level of this lower material, Sand Silt Tangential, of lower cohesion and plasticity that saturated, behaving in a semi-liquid way. Because this material is the whole foundation of the slope, its collapse caused all the rotational slip of the slope. It’s important to maintain the superior material of the slope, aiming at the reduction of shear forces and erosions.Keywords: Piezometric Level, morphometry, Break Circle.

2011 ◽  
Vol 28 (2) ◽  
pp. 151 ◽  
Author(s):  
R. A Ghani ◽  
T. L Goh ◽  
A. M Hariri ◽  
Y. N Baizura

The basic friction angle, Φb for artificially sawn discontinuity planes for fresh granite, as determined by tilt testing, has an average value of 30º. For the natural rough discontinuity surfaces, a wide range of values have been determined for the peak friction angle, Φpeak ranging from 47º to a maximum value of 80º, depending on the joint roughness coefficient (JRC). The average values of the friction angles for the different degrees of roughness were as follows: JRC 2–4 = 58°; JRC 6–8 = 60°; JRC 8–10 = 47°; JRC 12–14 = 60°; JRC 14–16 = 71° ; JRC 18–20 = 80°.


2021 ◽  
Author(s):  
Qingqing Yang ◽  
Fei Cai

Abstract A new analytical solution is presented for determining equivalent Mohr-Coulomb (MC) shear strength parameters over an arbitrary interval of minor principal stress σ3 from the generalised Hoek-Brown (HB) criterion using least squares method. Comparison with several published examples demonstrates that the proposed solution had a capacity to accurately determine equivalent MC parameters over a given interval of σ3, as well as instantaneous MC parameters by using a very small interval of σ3. EMC parameters depended heavily on the interval of σ3, which highlighted the importance of intervals of σ3. A calculation case shows that the equivalent internal friction angle and cohesion over the interval of σ3 from tension cut-off σcut−off to maximum minor principal stress σ3max were approximately 12% smaller and 10.3% larger than those over an interval from tensile strength to σ3max, respectively. The proposed solution offers great flexibility for the application of the HB criterion with existing methods based on the MC criterion for rock engineering practice.


2011 ◽  
Vol 250-253 ◽  
pp. 2161-2166
Author(s):  
Jun Zhao Gao ◽  
Guo Feng Xiao ◽  
Hai Qiang Miao

Side slop losing stability is one of the main factors which greatly influences freeway expedite construction, especially after side slop losing stability the determination of rock and soil mechanics parameter may take a long time. Inversion method to analyze slope stability can preferably solve the problem. During the treatment of the ecological freeway landslide, we can not obtain important Parameters due to great disparity of sample Parameters of landslide. However, using inversion method to get cohesion and internal friction Angle, and anglicizing its sensitivity during calculation of stability can identify reliable Parameters. According to slope stability calculus, the ecological reinforcement design scheme come into effect.


2009 ◽  
Vol 49 (3) ◽  
pp. 391-395 ◽  
Author(s):  
Mohsen Ghafghazi ◽  
Dawn Shuttle

Author(s):  
G S Hwang ◽  
D M Tsay ◽  
M H Huang

A universal form of profile equation for a plate cam whose follower has an oscillating motion and a convex arbitrary shape is derived in this study. The applied concept is the theory of envelopes in a parametric form. The derived results can be used to determine the profile of the cam with any kind of convex shape of the followers. It is also shown that the traditional followers, such as flat-faced and roller followers, are special cases of the universal form.


1996 ◽  
Vol 20 (4) ◽  
pp. 453-465 ◽  
Author(s):  
Robert J. Allison

Despite suggestions (see Wolman, 1995, for example) that problem-solving in physical geography relies increasingly on interactions between research and application, there is abundant evidence in hillslope studies of research focused on both real-world problems and aimed at generating new knowledge. A study of mass movement patterns (Flagollet, 1996) illustrates application, by examining hazard associated with spatial and temporal variations in landslide activity. Understanding the principle of dynamic equilibrium is, on the other hand, examined and verified using quantitative DEM data (Chandler and Brunsden, 1995) from sequential air photographs for a landslide complex at Black Ven, Dorset, UK. Some studies crosscut applied and basic research. Hazard assessment is one example, where Crozier (1996) uses past temporal records to address magnitude, fre quency and risk issues through the determination of trigger mechanisms and thresholds, rather than simply ranking terrain unit hazard susceptibility.


1985 ◽  
Vol 22 (3) ◽  
pp. 105-111
Author(s):  
A. L. Kryzhanovskii ◽  
Yu. S. Vil'gel'm ◽  
S. V. Medvedev

2013 ◽  
Vol 20 (2) ◽  
pp. 90-93
Author(s):  
Marzenna Popek

AbstractTransport of mineral concentrates is associated with high risk of liquefaction of the cargoes. This type of goods containing water may liquefy and shift dangerously across the cargo compartments. Therefore, it is rational to limit the moisture content of the cargoes which may liquefy. To prevent sliding and shifting of ore concentrates in storage biodegradable materials composed of starch are added to the mineral concentrates. The influence of adding starch materials to the mineral concentrates on its parameters determining ability for safe shipment was assessed on the basis of determination of the following parameters: permeability, cohesion and internal friction angle of concentrates.


2016 ◽  
Vol 21 (3) ◽  
pp. 5-14
Author(s):  
Mariusz Roland Rząsa

Abstract The paper presents an idea of a new measuring method based on image tomography. This method focuses on registration of images of bubbles moving in two perpendicular directions. Two images are used for determination of the center of mass, movement trajectory and local velocities. Volume and area of bubbles are defined by using approximation of the bubble shape with the known geometric figures. The paper also presents the algorithm of reconstruction of the bubble shapes and movement trajectories, as well as exemplary test results. The obtained results were compared with empirical correlations in the published literature.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Yanxi Zhao ◽  
Zhongxian Liu

Soil-rock mixture is a kind of unfavorable geologic material, and it is composed of low-strength soil particles and high-stiffness rock blocks. Mechanical properties of soil-rock mixture were controlled by the internal mesoscopic medium, thus resulting in great difficulties of determination of mechanical parameters. In this paper, influences of rock content, mesoscopic features, and random distribution of mixture in soil-rock mixture on its shear strength were discussed through discrete element numerical simulation of the laboratory triaxial test. Results demonstrated that, with the increase of rock content, the internal friction angle of soil-rock mixture increased continuously, while the cohesion of soil-rock mixture decreased firstly and then increased. The stress-strain curve belonged to a nonlinear hardening type, which was close to soil characteristic. However, the shear strength was affected by mesoscopic medium of mixture particles significantly, resulting in the strong discreteness of strength, and only by large amounts of data statistics can we get a better regularity of strength. The research results can provide references to determine mechanical parameters of soil-rock mixture.


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