This thesis analyses the deformation monitoring data inside and outside the tunnel

summarizes the deformation rules

and controls the tunnel risks based on the subway Cross Diaphragm（CRD）tunnel in compound strata of rock and soil of a typical city.The results show that over 60%of the total deformation inside and outside the tunnel is caused by the pilot tunnel excavation of the first two layers;the surface subsidence caused by tunnel excavation is relatively obvious

and the largest ground settlement site lies at the left side above the center line of the tunnel;tunnel face excavation has obvious influence on surface subsidence

with the horizontal range of influence being about 60meters;monitoring within the tunnel should be based more on vault settlement and be supplemented by horizontal convergence;vault settlement consists of piecewise curve

with the overall shape of decreasing and gradually stabilizing in the end.This thesis makes a conclusion by combining the deformation monitoring analysis with the field construction experience

which is as follows:close in a timely manner the initial supporting structure of the pilot tunnels on the first two layers during excavation;the distance between the tunnel face of two adjacent pilot tunnels should be controlled from 15to 20meters;the length of the steps should be controlled within 5meters;close the inverted arch timely

forming a loop.The above-mentioned measures will effectively control the deformation in or out of the tunnel and ensure the stability of the initial supporting structure.