Horizontal grouting construction method under closed environment

The invention discloses a horizontal grouting construction method under a closed environment. The horizontal grouting construction method comprises the steps that grouting is conducted on the obverseside of a tunnel, and lap joint is conducted by 10 m in each cycle of 50 m; and as for first circulating, seventy-six grouting holes are formed, wherein the depths of the B1-B9 holes are 15 m, the depths of the A1-A67 holes are 50 m, the diffusion radius is 1.3 m, a drainage hole is 40 m in length and formed in the bottom, a flowmeter is mounted at a drainage opening and used for counting the drainage amount. The horizontal grouting construction method under the closed environment is simple, convenient and high in operability; double control over the grouting pressure and the grouting amount is put forward, a 'double-control and speed decreasing' principle is adopted in the construction process, and a closed body and stratum deformation can be effectively controlled; the grouting order isthat grouting is conducted