喀麦隆南部地区风化壳特征分析

Analysis on Weathering Crust Features in South Cameroon

喀麦隆南部地区属刚果克拉通的组成部分,自寒武纪以来,没有受到造山运动的影响,地壳长期稳定。该地区完整岩体之上普遍发育厚度5～30 m不等的风化壳,而且具有典型的砖红土型风化壳的特征,自上而下,依次为砖红土带、高岭石残积层带和碎石-角砾残积层带。受其影响,该地区完整基岩面高低起伏,变化无常。由于风化壳内残积层的力学强度普遍较低,其下部随机分布有块径2～4 m的完整块石,极易引发建筑物地基不均匀沉陷等工程地质问题。

Hie south Cameroon is a part of Congo Craton,it is not affected by orogeny since the Cambrian,so the crust is very stable.This area develops 5-30 m thick weathering crust above the intact rock mass,and is characterized by typical laterite weathering crust.It is laterite zone,kaolinite eluvial zone and rubble-breccia eluvial zone from top to bottom.Influenced by this,the intact bedrock surface in this area is steep.Since the mechanical strength of eluvium in the weathering crust is generally low,and the underlying is randomly distributed with intact rock of 2-4 m in diameter,it is easy to cause engineering geological problems such as uneven settlement of the foundation.