Analysis of safety factors for roads slopes in central Africa

Ngapouth, Ibrahim Mbouombouo; Meli’i, Jorelle Larissa; Gweth, Marthe Mbond Ariane; Pokam, Blaise Pascal Gounou; Koffi, Yvonne Poufone; Njock, Michel Constant; Nkoma, Michel André Pouth; Nouck, Philippe Njandjock

doi:10.1016/j.engfailanal.2022.106359

Cited by 8 publications

(9 citation statements)

References 15 publications

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“…Although not widely reported in Central Africa, these movements are very recurrent and produce scouring of culverts, collapse of structures (bridges, scuppers, etc.) [7], landslides (Figure 1) [8][9][10], and slope failure, as studied in the work of Biswas et al [11] and Mbouombouo et al [12], in which it is established that slopes become unstable for slope values greater than 6.17 • in sandy-clay formations and for slope values greater than 10 • in gneissic formations, respectively. Figure 1, based on the literature review, shows that roads are generally subject to rockfalls, collapses (longitudinal and transverse) and shears (longitudinal and transverse), which very often precede collapses.…”

Section: Introductionmentioning

confidence: 94%

“…Field campaigns were carried out during the dry season from 2019 to 2023 using compasses, GPS, distance meters and altimeters to identify fault zones and areas of possible landslides [12], particularly on the N3 national road. This road was chosen as the pilot zone because it is the main road linking the port area (from the Atlantic Ocean) to all the other countries in Central Africa and belongs to both the equatorial zone and the coastal zone, characterized by a high level of cloud cover.…”

Section: Field Datamentioning

confidence: 99%

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Possible Influence of Brittle Tectonics on the Main Road Network Built in the Central African Environment Using Remote Sensing and GIS

Tchato,

Gounou Pokam,

Ariane Gweth

et al. 2023

Sustainability

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The construction of sustainable road and highway networks in the world, despite numerous feasibility, pre-feasibility and execution studies, are always confronted with the demands and vagaries of foreseeable and unforeseeable natural disasters. Studying cyclones, earthquakes, fracturing and landslide zones along roads is therefore a challenge for the sustainability of these infrastructures. In many countries around the world, the methods generally used for these studies are not only expensive and time-consuming, but also the results obtained are not always efficient. This work examines whether Landsat 8 (with a high cloud level) and SRTM data can be used in both equatorial and coastal Central Africa zones to produce relevant mapping, locating fracture and landslide zones, in order to contribute not only to a better road layout at lower cost and in a relatively short time, but also to a better prevention of geological disasters that may occur on its network. To this end, a map of the main road network was produced and validated with field data, as well as the maps of the main unstable slopes, faults and fractures zones intersecting the road or highway network. These approaches are useful for sustainable planning, management, monitoring and extension of roads worldwide, especially in Central Africa.

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Section: Introductionmentioning

confidence: 94%

Section: Field Datamentioning

confidence: 99%

Possible Influence of Brittle Tectonics on the Main Road Network Built in the Central African Environment Using Remote Sensing and GIS

Tchato,

Gounou Pokam,

Ariane Gweth

et al. 2023

Sustainability

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“…Paliwal et al [19] coded artificial neural network algorithms and developed an Android application to instantly predict the stability of residual soil and the rock slope. Ngapouth et al [20] used a combination of geometric, kinematic, and seismic methods to analyze the stability of cut slopes affected by falling particles and block settlement. Kumar et al [21] used a multi-geophysical approach for site response analysis and adopted vulnerability analysis to identify the weak area of the surface.…”

Section: Introductionmentioning

confidence: 99%

Stability Analysis of an Unstable Slope in Chongqing Based on Multiple Analysis Methods

Li¹,

Hu³

et al. 2023

Processes

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The failure of an unstable slope has the characteristics of sudden disaster, rapid sliding speed, and a wide range of influence. This study selected an unstable slope in Chongqing as the evaluation object, divided it into the strong-deformation zone and weak-deformation zone, and analyzed its formation mechanism and deformation failure mode. Macroscopic qualitative analysis was processed by the geological exploration method, the slope stability and the sliding thrust were quantitatively analyzed by the limit equilibrium method, and the sensitivity analysis was calculated and conducted on its shear strength parameters by laboratory tests and a field large shear test. The historical formation process of the slope was deduced, and suggestions for the prevention and control of unstable slopes were proposed. Studies show that the deformation mechanism of an unstable slope is a push type, its deformation is mainly concentrated in the southern area of the rear edge, and the width of the slope ground tensile crack is 1~30 cm, with a visible depth of 3~30 mm and an extension of 3~12 m. The shear strength of potential sliding zone soil in the weak-deformation zone is: cpw = 35.70 kPa, φpw = 14.80°, and in the strong-deformation zone it is: cps = 32.54 kPa, φps = 13.54°. The results show that the formation of a steep cliff by the artificial mining of sandstone is the main cause of slope deformation, the action of groundwater is the main triggering factor for slope deformation, and the inclined rock mass at the front edge is the key block for the deformation. The strong-deformation zone of the slope is in an unstable state under rainstorm, and the weak-deformation zone of the slope is basically-stable under rainstorm. Unstable slopes are prone to slide during a rainstorm period, which threatens the lives and properties of the residents and road traffic safety around the slope. The research results provide an important theoretical basis and data support for the accurate judgment and stability analysis of instability failure modes and for the further effective prevention and control of unstable slopes.

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“…However, the sedimentary deposits generally encountered there, which are sometimes loose in consistency, pose the thorny problem of their recognition in order to guarantee the stability and durability of the foundations of the future structures that will be built there, which are essential conditions for their operation, durability and economic profitability [3][4][5]. The study of foundation anchorage conditions for structures in sedimentary estuaries is therefore a challenge for scientists in general and engineers in particular [1][2][3][4]6]. The Wouri estuary (Figure 1) is a large estuary in Central Africa, where several rivers join and flow into the Gulf of Biafra [5,7,8].…”

Section: Introductionmentioning

confidence: 99%

“…2022, 12, x FOR PEER REVIEW 2 of 34 be built there, which are essential conditions for their operation, durability and economic profitability [3][4][5]. The study of foundation anchorage conditions for structures in sedimentary estuaries is therefore a challenge for scientists in general and engineers in particular [1][2][3][4]6]. The Wouri estuary (Figure 1) is a large estuary in Central Africa, where several rivers join and flow into the Gulf of Biafra [5,7,8].…”

Section: Introductionmentioning

confidence: 99%

An Attempt to Study Foundation Anchoring Conditions in Sedimentary Estuaries Using Integrated Methods

et al. 2022

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The search for and knowledge of the best conditions for anchoring the foundations of certain structures such as bridges, tunnels and quays in sedimentary estuaries is a challenge, for both scientists in general and engineers in particular. Indeed, wharves are structures that receive a lot of stresses and therefore require anchoring to avoid tilting and to guarantee their stability during service. This work, based on the analysis of data from seismic refraction methods, mechanical soundings and laboratory tests, characterises the terrain of the Wouri estuary in Central Africa. The objective is to determine and present the subsurface layers encountered as well as their characteristics, in order to define the best conditions for anchoring the foundations to ensure the stability of the quays to be built there. The seismic refraction campaign shows that the study area is relatively heterogeneous over the first 25 m, with velocities measured in the range 1520–1750 m/s; modulated in two distinct ranges, between 1520–1580 m/s characteristic of mud and loose sediments (alternating layers of clay, sand, loose silt) and the range 1580–1750 m/s corresponding to the signature of sandy-silty or compact clays. The mechanical tests show sedimentary soils, with alternating layers of sandy clay and clayey sand over the 42 m drilled, loose over the first 30 m in the bank area and over the first 15 m in the canal or dredge area, with a limit pressure of less than 1 MPa. Similarly, the soil samples taken and tested in the laboratory show that the soils are clayey over the first 30 metres, plastic and liquid with respect to their water content, respectively, below and above the liquidity limits, confirming their loose character. The results of seismic refraction, mechanical soundings and laboratory tests show that, in estuarine areas characterised by alternating sandy clay and clayey sand, there are not always hard formations in the first 25 metres of depth but, from a depth of 30 m, the soils become moderately compact and begin to form an anchoring layer sufficient to guarantee the stability of the quays against earth pressure forces.

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Analysis of safety factors for roads slopes in central Africa

Cited by 8 publications

References 15 publications

Possible Influence of Brittle Tectonics on the Main Road Network Built in the Central African Environment Using Remote Sensing and GIS

Possible Influence of Brittle Tectonics on the Main Road Network Built in the Central African Environment Using Remote Sensing and GIS

Stability Analysis of an Unstable Slope in Chongqing Based on Multiple Analysis Methods

An Attempt to Study Foundation Anchoring Conditions in Sedimentary Estuaries Using Integrated Methods

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