Construction method for reinforcing soft formation in shield construction

The invention discloses a construction method for reinforcing soft formation in shield construction, adopting a reinforcement mode which uses plain continuous walls as the major and jet grouting piles as the auxiliary; as the plain continuous wall is adopted in the invention, with partial support, the plain continuous wall can withstand external soil-water pressure to ensure the stability of a working face, and tunnel portals can be broken down in advance before launching shield construction to prevent confliction with the shield assembly and debugging; the bulk breaking and construction can be safely and quickly carried out on a connection access; the construction process is simplified; the requirements on plain continuous wall are relatively simple, joints do not need to be specifically made, then a pile jetting machine is adopted to punch continuously in the construction process; after the plain continuous wall is used for reinforcement, the reinforcement range is significantly reduced, particularly applicable for engineering sites with small construction sites, intensive underground pipelines, heavy traffic on the ground and near to the foundations of the buildings on the ground; the reinforcement cycle is shortened, the age for reaching required strength is short, and the cost of the entire end is relatively low.