Studay On The Assessment And Defending And Preserving Decision System Supported By Gis Of Adjoining Underground Pinpelines Damage Caused By Tuunel Excaving

Urban underground space's development and utilization is the development trend of modernization construction in the present world, is the only way to realize the sustainable development of urban construction. Along with the rapid development of china's economy, construction of urban underground space also flourished. With its synchronization ,the underground engineering construction disturbance effecting on the environment has become more and more serious, tunnel excavation disturbing environment is the most typical in urban underground engineering. Urban tunnel construction inevitably disturbs surrounding geotechnical, then effects on the buildings (structures )and adjoining underground pipelines, endangers building (structures) and adjoining underground pipelines security when seriously affected. Studies of the effect on geotechnical deformation and effect of adjoining underground pipelines caused by urban tunnel excavation, has important significance in ensuring the safety of existing facilities and normal use. This paper with geotechnical deformation for research as the starting point caused by tunnel excavation, systematic study on the underground pipelines'effects of geotechnical deformation caused by tunnel excavation, takes GIS geographic information system as software platform, takes pipelines'damage-evaluation and defending and preserving decision as the main contents research, overall deeply study, provides theoretical foundation and technical route for the disaster prevention and mitigation of underground pipeline during tunnel excavation, the main research contents include:1. Briefly introduces some characteristics of geotechnical deformation, on the distribution Curve characteristics of surface subsidence,horizontal displacement distribution,surface incline,horizontal deformation and surface curvature is analyzed;2. Discusses the influence and damage mechanism about geotechnical deformation caused by tunnel excavation to surrounding underground pipelines, summarized respectively the influence of underground pipelines caused by surface subsidence,surface uplift,surface inclined,surface curvature deformation and horizontal distortion five forms of existence; 3. Introduce the surface deformation forecast method, mainly include analytical method,the numerical simulation method,the method of geotechnical centrifuge simulation experiment,elastic foundation beam analysis method and engineering analogy method;4. Tunnel excavation has a strong space effect. In this paper, subsidence simulation software is used for the excavation of shallow tunnel excavation. This paper obtains the overlying soil sink valu By simulation calculation software in the method of shallow tunneling method to excave tunnel, gets each point of tunnel surrounding soils subsidence,according to the isoline to determine the scope of influence of excavation disturbance, and according to the isoline map to calculate pipeline each of discrete sinking points5. The Purpose of previous work study is about the evaluation of its internal forces for the pipeline under loads. This paper is focusing on the stress-strain problem caused by the deformation of pipeline and the finite element analysis software-ANSYS is used to calculate and analyze the impact of the surrounding soil and neighboring pipeline by the tunnel excavation,which is different from the majority research workers' idea.6. Based on the GIS platform, the damage-evaluation and preserving decision-making decision system for the underground pipeline is developed. According to the relevant norms and standards, decision-making standard database is establish on the stress-strain limit criteria of the underground pipeline, and then in the actual it is used for the damage-evaluation and preserving decision-making in underground pipeline, so as to realize digital management for the damage of underground pipeline caused by underground excavation,and then provided an important technical support for the "prevention" and "mitigation" of the modernization pipeline. Research results can be further enriched deformation control design and improve the reliability and safety of design to reduce the accidents caused by tunnel excavation.