Application of high-precision three-dimensional mapping technology in urban housing structural safety inspection

In this paper, the streak array detection method is used to improve the accuracy of LiDAR distance detection and to determine the three main types of errors of its technology. Through the centre-of-mass weight method, the center-of-mass position of the signal distribution is calculated to determine the target distance. Combined with the inertial navigation system and the distance inverse algorithm, the coordinates of the object points in the carrier coordinates are obtained, and the coordinates of the housing structure in the geocentric right-angle coordinate system are obtained. Based on the RANSAC algorithm, combined with the eigenvalue method for feature extraction and planar simulation of 3D point cloud data, to obtain accurate fitting data and from the three aspects of size, flatness, and verticality for the safety inspection of urban housing structures. The converted values of compressive strength of sampled wall masonry mortar, converted values of compressive strength of wall masonry bricks, presumed values of concrete strength at the current age of beams, and the spacing of reinforcement at the bottom of cast-in-place slab slabs were 3.948-4.525 MPa, 7.376-8.257 MPa, 23.551-26.487 MPa, and 132-242 mm, respectively. In order to solve the superstructure stiffness inhomogeneity caused by the settlement of the house structure, the finite element modelling was used to analyse the change of the uneven settlement in different cases, and when the modulus of elasticity was modified from 2.55* 10⁴ MPa to 2.80* 10⁴ MPa, it had a positive effect on the settlement of the bottom settlement columns and the peripheral columns, and it was learnt from the analysis of the additional settlement values of the second settlement columns that the values of the settlement of the columns were 24.588, 27.841, 28.854, 32.182, 33.148, 27.398, 31.985.