Applying BIM technology and threedimensional las...
By using a three-dimensional laser scanner to scan the inner surface of the tunnel panoramically,the point cloud data on the inner surface of the tunnel were obtained[2].By comparing the point cloud data with BIM model which is based on completed drawings,the data of internal structure deformation of the tunnel was obtained.By using the obtained data and referring to the national standard of“Technical Specification of Maintenance for Highway Tunnel”(JTG H12-2015),this study formulated the structural safety assessment criteria for existing urban underpass tunnels and compiled maintenance suggestions.It can be mainly used to solve the following problems.
(1)The deformation trend of tunnel structure can be predicted by comparing the point cloud data obtained by scanning the tunnel at intervals of time.However,some tunnels have been built for a long time.When the tunnel was just completed,it was not scanned by a three-dimensional laser scanner,and the initial point cloud data of the tunnel missed,so it is not conducive to deformation prediction.
This study established a BIM model of the initial state of the tunnel when it was completed,and took this model as the initial state of the tunnel,so that the structure without the data of the point cloud at the completion time could have the initial observation value.Then the BIM model was compared with the point cloud model.The data obtained from the comparison presented the deformation of the structure,so as to predict the deformation trend of the structure.This study can ensure that the structural deformation of the tunnel under the tunnel is within the safe range(Figure 3).
Figure 3 Data comparison betw een BIM model and point cloud model
(2)By inputting structural disease records into the BIM model,managers can easily find and record structural disease data,so as to achieve the purpose of timely recording and eliminating structural safety hazards of urban underpass tunnels(Figure 4).
Figure 4 Recording structure detection image and location in BIM