This shoring system enters in the category of slide rail shoring systems, including rails, panels and strutting assemblies. It applies on shoring of excavations of various shapes such as trenches, rectangular and polygonal pits of great or lesser depth. Rails are of two types, linear or corner rails. Pairs of linear rails are spaced apart along excavation so that a strutting assembly keeps opposite rails of a pair of rails pressing against wall of excavation; corner rails are placed on the corners of any polygonal shaped excavation. Shoring panels slide vertically between adjacent rails creating a shoring wall on two or more sides of excavation. Rails have opposite sides provided with an outer and an inner guide for sliding vertically panels. The outer guide runs the full length of rail while inner guide is halfway from the bottom up reducing the weight of rail and easing installation and removal of panels. The corner rails are adopted to shore pits of polygonal shape of four or more corners eliminating the need of cumbersome strutting assemblies inside excavation. Linear rails have frontally an external edge guide so that at least one strutting assembly slides interlocked between two oppositely held linear rails. The strutting assembly has a horizontal spreader and two vertical members and is modulable by mean that two or more of them could be assembled together using vertical extension members. Strutting assembly is provided with rollers to ease its vertical mobility. Shoring panels are of equal design and access the rail laterally by swinging within outer and inner guides.