Abstract: The weak-and hard alternating rock layers are frequently encountered in the sedimentary rock formations. However, these rock strata, especially, weak rock layers, are the unfavorable geological conditions for the rock socketed piles. In order to accurately determine the axial bearing resistance and the rock socketed depth, the performance of the weak-and-hard alternating rock layers should be thoroughly investigated. If the compressive strength of rock loading bearing layer are low or the assumed design values are low, the total bearing resistance of the rock socketed pile could be achieved by using a larger diameter pile or a deep rock socketed length. When pile tip is at the slightly weathered rock layer and the shaft is penetrating one or more weak zones, the side frictions in the weak rock layer should be reduced.

Key words: Rock Socketed Piles, Pile Supported Raft Foundations, Weak-and-Hard Alternating Rock Layers, Intermediate Geo-materials, Soften