Study on Mechanical Characteristics of Tunnel Support System in Sandy Cobble Stratum

摘要

Because the sand gravel stratum with loose structure, good gradation, easy disturbance, poor stability, deformation and other characteristics of long duration, large deformation and collapse failure phenomenon is extremely easy to cause in the tunnel construction, leading to a primary support structure for strong deformation or even destruction, serious impact on the tunnel construction and safety, is one of the main problems encountered in tunnel construction. The paper based on the engineering background of Gongboxia sand gravel stratum tunnel, studied the Sandy pebble tunnel primary support stiffness and the influence of strength characteristics, also mechanical impact characteristics of secondary lining and timing. By studying the mechanical behavior of tunnel support system, the paper puts forward the parameters of the initial support of the sand gravel tunnel, and makes clear the relationship between the stress of the supporting arch and the stress of the lining and the timing of the two lining. The research results can provide supporting design reference for sand pebble stratum tunnel and similar projects.