The invention relates to the field of
tunnel construction, in particular to a method for constructing a tunnel by finishing full section curtain grouting from an upper-half section, which solves the problems of long construction period, difficult construction, high construction
safety risk and the like during full section curtain grouting construction of a complex
geological section. The method comprises the following steps of: firstly, excavating the upper-half section, and strengthening the support of a tunnel face; secondly, constructing a temporary inverted arch and a
grout-stopping wall of the upper-half section; thirdly, excavating the lower-half section in place, and strengthening the support of the tunnel face; fourthly, constructing a
grout-stopping wall of the lower-half section; fifthly, forming grouting holes on the upper-half section, wherein the maximum
elevation angle alpha is between 25 and 45 degrees, the maximum depression angle beta is between 30 and 70 degrees, andthe longitudinal strengthening length is between 15 and 30 m; sixth, performing grouting operation; seventh, constructing a large-scale lead
pipe roof; eighth, excavating a
grout-stopping wall; ninth, excavating a tunnel
trunk; and finally, continuously
cycling by taking an area of 15 to 30 m as a grouting strengthening
cycling section to realize the construction of the tunnel by curtain groutingfrom the upper-half section. The method can greatly reduce the construction difficulty, shorten the construction period, and ensure the construction quality, and the construction is safe, quick and economic, so the method can be widely used in the field of
tunnel construction.