A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
The 1988 Nanka landslide, Anambra state, Nigeria
Abstract In 1988 a major landslide which required the evacuation of more than 50 families occurred in the little town of Nanka in Anambra State, Nigeria. Investigation revealed that the landslides were caused by an overconsolidated, very highly plastic mudstone layer (PI=67) which probably contained quantities of montmorillonite clay. Peak strength values of remolded samples of the mudstone measured in the ordinary shear box test differed from those of non-remolded (intact) samples only in showing zero cohesion. These values probably represent the strength of the mudstone in its normally consolidated condition. Stability analysis indicated that the major slide approximated more to a sliding block than to a circular failure with the mudstone layer as the base. It also showed that the peak strength at which the major slide occurred probably represents the strength of the mudstone in its fully softened or critical state, while the residual strength at which the minor slides occurred probably represents the strength at large displacements when perhaps the clay particles had become highly oriented in the direction of movement. In the present study, for the first time, the landslides in the highly unstable Nanka area are explained by the presence of active clays.
The 1988 Nanka landslide, Anambra state, Nigeria
Abstract In 1988 a major landslide which required the evacuation of more than 50 families occurred in the little town of Nanka in Anambra State, Nigeria. Investigation revealed that the landslides were caused by an overconsolidated, very highly plastic mudstone layer (PI=67) which probably contained quantities of montmorillonite clay. Peak strength values of remolded samples of the mudstone measured in the ordinary shear box test differed from those of non-remolded (intact) samples only in showing zero cohesion. These values probably represent the strength of the mudstone in its normally consolidated condition. Stability analysis indicated that the major slide approximated more to a sliding block than to a circular failure with the mudstone layer as the base. It also showed that the peak strength at which the major slide occurred probably represents the strength of the mudstone in its fully softened or critical state, while the residual strength at which the minor slides occurred probably represents the strength at large displacements when perhaps the clay particles had become highly oriented in the direction of movement. In the present study, for the first time, the landslides in the highly unstable Nanka area are explained by the presence of active clays.
The 1988 Nanka landslide, Anambra state, Nigeria
Okagbue, C. O. (author)
1992
Article (Journal)
Electronic Resource
English
BKL:
56.00$jBauwesen: Allgemeines
/
38.58
Geomechanik
/
38.58$jGeomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
56.00
Bauwesen: Allgemeines
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB18
The 1988 Nanka landslide, Anambra state, Nigeria
| Online Contents | 1992
Technology Gap Efficiency of Small-Scale Rice Processors in Anambra State, Nigeria
| DOAJ | 2023
| BASE | 2020
Quality Assessment of Direct Harvested Rainwater in parts of Anambra State, Nigeria
| BASE | 2012
| BASE | 2015