Abstract:

There is much experience and lessons related to tunnels crossing underneath existing highways, railway, buildings and structures at home and abroad, however, there are rare tunnels crossing underneath existing airports. In the paper, the characteristics of the surrounding rock pressure of a mined tunnel crossing underneath the runway of Beijing Airport are studied. First of all, a monitoring plan is proposed on basis of the geological conditions and the support features of the tunnel; then, the earth pressure is calculated on basis of the theoretical knowledge; at last, field tests are made on the surrounding rock pressure of the mined tunnel under dynamic load and static load respectively and the tests results are compared and analyzed. The study results show that the surrounding rock pressure at the test crosssections under both dynamic load and static load are within the allowed range, the surrounding rock pressure under the dynamic load increases by 45% to 88%; from the viewpoint of distribution pattern, neither the distribution of the surrounding rock pressure under dynamic load nor the distribution of the surrounding rock pressure under static load is uniform, and relatively speaking, the former is more uneven, however, they both exhibit the following characteristics: the surrounding rock pressures at the tunnel crown and at the tunnel invert are larger, while the surrounding rock pressure at the arch waist is smaller. 

Key words: aircraft dynamic loading, mined tunnel, surrounding rock pressure, field test