Contrastive Study On Construction Mechanical Behavior For Highway Multi-Arch Tunnel And Neighborhood Tunnel

Space between left and right of twin-tunnel can't meet the request of code,oweing to the limit of especial geology, landform condition, join means, collectivity linetype and engineering cost.In the best interest of techno-economy benefit and entironment benefit, multi-arch tunnel and neighborhood tunnel become important choice schemes especially in short or medium length tunnel and the adit of long length tunnel.Besded on the research of key design and construction technology for neighburhood tunnel and the research of synthesis construct technology of multi-arch road tunnel,the result were contrasted Colligating all research,the main contents of this thesis are as follows with the result of the acquisition:(1)The concrete is applied as pivot and trans-force point in the mid-wall of multi-arch tunnel, so the mid-wall becomes the one of the most important parts. It accords with the design way of structure mechanics, which makes the whole tunnel structure suffer load reasonable and controls the support capacity of the mid-wall contrived. The neighborhood tunnel makes full use of the support capacity of the center pillar ground by reinforcing and arranging the steps of construction reasonable, which can eliminate the effection on the ground and the lining structure during the excavation process. This accords with the design method of NATM.(2)Some results can be acquired by the contrast of the construction methods between the multi-arch tunnel and the neighborhood tunnel. The depart construction of the twin-tunnel can reduce the excavation above 10%, and in the same category of ground, the construction steps of the neighborhood tunnel are better than the multi-arch tunnel.(3)The A kind of neighborhood tunnel is constructed in soft and crushed ground. The center pillar need to be reinforced largely, so the difficulty of the construction is also more large and the stability of the center pillar can't be promised. Whatever, the mid-wall of the multi-arch tunnel is made by the concrete, which can assure the support capacity and the stability. So it should be contrasted and choiced in the view of the structure safety in the soft ground. (4)By the research method of numerical calculation, similitude model test and the in-site test, it gets some results. The design strength of prime support in the A kind neighborhood tunnel should be more than the multi-arch tunnel, but the B and the C kind neighborhood tunnel should be less than the multi-arch tunnel. The design strength of secondary lining should be equal the multi-arch tunnel.(5) The mid-wall of the multi-arch tunnel bears up the overburden load and the top load passed by the prime support of the left and the right tunnels. But in the neighborhood tunnel, the mid-wall only bears up the overburden load. So under the same category of surrounding ground, the load beared by the mid-wall is less in the neighborhood tunnel in the same depth of earth covering.(6)With the structure style and the deformed character of the multi-arch tunnel and the neighborhood tunnel, the important point of in-site measure, the combination of the monitor contents and the benchmark of the monitor should be established...