Due to the performance improvement of construction machines and the increase in case studies in mountainous areas, cases have increased where the pile foundation is supported by a bedrock as a bearing layer. In a rock layer that is thought suitable as a load bearing foundation because of its high strength and high deformation modulus compared with those in general ground, it is considered that the embedded length into rock could be shortened if a rational design method were established. Consequently, the existing knowledge and guidelines are sorted out in this paper, focusing on the characteristics of rock mass, modelling of horizontal bearing capacity characteristics of foundations, and the behavior of short piles subjected to lateral loading, for extracting issues arising when proposing cantilevered steel tubular pile retaining walls with shortened embedded length in a relatively stiff rock layer. At the end, issues arising at a time of making the embedded length shorter in a rock layer will be described.
