Abstract: In Fuzhou, the bored section of the Hudongdonglu tunnel passes through a sandy strong weathered granite stratum and therefore requires strict control of surface deformation. Horizontal jet grouting piles pre-reinforcement technology was adopted in its design. In order to guide construction and identify the key points for tunnel construction monitoring, a study on the pre-reinforcement effect of horizontal jet grouting piles and the law of tunnel structure displacement was performed using the 3D elasto-plastic finite element method. Study results show that with reinforcement with horizontal jet grouting piles, compared to construction with no horizontal jet grouting piles,the final settlement of the arch crown was reduced by 63.45%, the longitudinal displacement of the tunnel face was decreased by 69.6% and the plastic strain area of the tunnel face was reduced dramatically. The pre-reinforcement by horizontal jet grouting piles effectively controls the deformation and has a remarkable reinforcement effect.