Guiding device for supporting construction of foundation pit in narrow zone and construction method

The invention provides a guiding device for supporting construction of a foundation pit in a narrow zone and a construction method. The structure is as the follows that an original box culvert is cutinto two sections of a front section and a rear section by an intercepting well; an inner circle and an outer circle of high-pressure jet grouting piles are constructed at the periphery of an intercepting well foundation pit; H-shaped steels are interpolated in modes of closely inserting and inserting one by one with one interval; the outer circle of high-pressure jet grouting pile is arc-shaped,and the positions, the right above the front section and the rear section of the original box culvert, of two ends of the outer circle of high-pressure jet grouting pile are connected with the inner circle of high-pressure jet grouting pile through full reinforcement of the high-pressure jet grouting pile; a reinforced concrete inner support is arranged between the inner circle and the outer circle of high-pressure jet gro