Application Research On Deformation Of Foundation Pit Of Using DLT Method With Additional Conditional Constraint Conditions

With the the process of urbanization accelerating unceasingly, the state has increased investment in infrastructure construction, has also increased the number of underground engineering year by year. The accidents caused by foundation pit become more and more, so people begin to pay much attention to the deformation monitoring of foundation pit. Traditional deformation monitoring based on total station and inclinometer or other instrument as the means of measurement method, but the two methods have long operation time and site construction interference and other issues.To solve these problems, with the close-range photogrammetry technology playing an increasingly important role in deformation monitoring, especially the emergence of digital SLR camera, it provides a new method for measuring deformation monitoring of foundation pit. The significance of using the method of close-range photogrammetry, is not only because of its advantages of non-contact observation, mainly the widespread use of computer in recent years. So that people can take advantage of the strict numeric modeling method to simulate the photogrammetric system errors in the process, which significantly improve the accuracy of photogrammetric points. Because of these advantages, the close-range photogrammetry technology is very suitable for measuring the target bodys that contain a large number of measurements,and also in the more suitable to film a dangerous photographic objects to improve the safety factor,especially when the monitoring object is some special terrain.In this paper, it takes an example to reaseach the subway foundation pit.This paper focuses on the actual project cases, put forward an point extraction method to obtain precise pixel coordinates according to the characteristics of the underground excavation engineering.lt focuses on the analyzing and elaborating the model of additional conditional constraint conditions DLT on the deformation monitoring of foundation pit.The process achieves by programming in matlab.Then it proves the feasibility of this approach by comparing with the data of coordinates calculated by this model and the software Lensphoto 2.0 data.At the same time,it puts forward some problems and looks forward tothe future research work.