The invention provides an in-situ test method for a deeply-buried soft-
rock tunnel. The in-situ test method comprises the first step of conducting sampling on an early-stage exploration tunnel to obtain distribution characteristics of in-situ stress fields, the second step of calculating and determining parameters of a
simulation test tunnel, the third step of excavating and expanding a size effect transition section, the fourth step of calculating and determining positions of monitoring sections, the fifth step of arranging an observation
branch tunnel and pre-burying monitoring instruments, the sixth step of excavating the
simulation test tunnel, and the seventh step of conducting regular observation through the monitoring instruments. The invention further provides an in-situ
test structure for the deeply-buried soft-
rock tunnel. The in-situ
test structure for the deeply-buried soft-
rock tunnel is established according to the in-situ test method. The in-situ
test structure comprises the
simulation test tunnel, the early-stage exploration tunnel and the observation
branch tunnel. By the adoption of the in-situ test method and structure, anisotropism and size effects of soft rock are truly represented, a large quantity of measured data and test information of the properties of surrounding rock can be obtained, the uncertain factors that deeply-buried soft rock are low in strength and prone to
softening with water, and a high deeply-buried
cave section is hard to form are avoided, the defects of existing
monitoring methods and tests are effectively overcome, and a reliable data support is provided for analysis of stability of the tunnel.