Study On The Subgrade Diseases In Permafrost Of Qinghai-tibet

In recent years, with the rapid growth of national economy, which led to the development of therelated infrastructure, the tunnel engineering without exception has also got rapid development. For tunneldesigners, the design of the current task is becoming very heavy and the workload of drawing is also veryhuge, so the system of CAD software is urgently needed to be greatly improved.Usually, the conventional design of the highway tunnel is focusing on solving the problems of thecross sectional design, the profile design, the portal design and the lining design. But the portal design isone of the difficulties in developing the tunnel CAD software. It is because that tunnel portal contains alarge amount of information which is much more complex and difficult to unified and standard. So onlyusing the development of parametric system can greatly improve the design efficiency and specifies thedesign object by continuously adjusting the input parameters which are controlled the effect of thegraphical output.The research subject of this thesis is the design of the end wall portal which is very common in tunnelportals, basing on the parametric technology as the guide and using the VBA which is the secondarydeveloping tool of AutoCAD to write the design program. The function of this design system is that can beautomatically generating three views of the portal and checking the strength and stability of the portal withentering the appropriate control parameters. By the design system of the end wall portal shows thatparametric drawing can be used to develop the tunnel CAD system as the dominant idea. The purpose ofthis thesis is not to develop a complete tunnel aided design CAD system, but through the end wall Portalaided design as an example to show that, in the tunnel design work, according to actual needs, the designerscan use the AutoCAD secondary development tools to write the corresponding design process to improvethe design efficiency and simplify the complicated design work.The program is based on the AutoCAD as the operating platform, VB as a development language,VBA as the development tool, to achieve parametric drawing and Computation of the end wall Portal. Thestudy of this thesis is an attempt to develop the Portal aided design and also has a certain reference value todevelop the tunnel CAD software based the VBA.