Model Test Of The Behaviors Of Buried Pipeline Under The Environment Of Ground Fissure

With the continuous development of social economy, the normal operation of all kinds of buried pipelines, including Gas, heating, water supply, drainage pipelines, is playing a more and more important role in maintaining citizens’ daily life. However, Xi ’an, as a world famous city, urban construction, people’s production and living are under the threat of serious ground fissure geological disasters which is the most typical urban geohazards in Xi’an.So far, 14 ground fissures are founded in Xi’an with an extended length of more than 100 km and a covering area of more than 150 km2. These ground fissures go through Xi’an city from northeast to southwest with an approximately parallel distribution. Different from general buildings, as a kind of linear engineering, the urban buried pipeline can’t avoid ground fissure area,and therefore going through the ground fissure area is the only option.Ground fissure activity has brought serious security hidden danger to the large-scale urban pipeles in Xi ’an city.In this paper, taking theburied pipeline facing the threat of ground fissures as research background and on the basis of previous damage of buried pipeline induced by ground fissures’ activity, the physical model tests have been carried out on large scale settlement platform and the model box system developed by Chang’an University to discuss the reaction of buried pipeline under the action of ground fissure, which include a concrete one aiming at the old concrete buried pipeline and a SRTP one. Force bearing status, deformation and failure mode were analysed. The model test results show that in the ground fissure area, whichever layout mode of buried pipeline is(riding or joint riding across ground fissure), old concrete pipe can be considered for replaconcrete when differential settlement of ground fissure reaches s = 6 cm. Through the model test of SRTP one and numerical simulation, it is found that the influence range of ground fissure activity to this kind of pipeline is mainly concentrated in the region from 1 m at the foot wall of the ground fissure to 2 m at the hanging wall of the ground fissure. And the calculation method of pipe- soil interaction is put forward. The above results have an important directive significance in Xi "an urban pipeline construction and old pipe network transformation and also are of a reference value to thepipeline project construction in other ground fissure area in China.