The present invention discloses a system and method for constructing retaining wall structure and well point in granular soils under groundwater level. The system is configured to drain the excavated zone and stabilizes the soil slope wall especially in urban lands with granular soils and high groundwater level during construction process. The system is configured to enable installation of vertical beams and polyethylene grooved drainage pipes wrapped by geotextile for drainage in the boundaries of the desired land by using a hammering casing pipe system. The hammering casing pipe system comprises a casing to receive the vertical beam and the drainage pipe, a mandrel for inserting the casing to the target location without removal of soil in the casing, a hammer element for hammering the mandrel into the target location, and a steel shaft or an impact transmission shaft configured to transfer impact from the hammer element to the mandrel.