Research On The Key Issues In The New-style Highway Survey And Design Based On Geotechnology

The development of economy and society in China accelerates the highway construction and development. The network of highway in the east and partial middle region of China has been accomplished, and it has been extended to the middle and the west of China. Nowadays, the highway construction mainly converges at the mountain areas with lofty and precipitous peaks, where the terrain condition is awful and geological conditions is complicated, and the basic data is almost empty. In the highway construction, technology required is more, the period is shorter, and the task is heavier. More strict requirements for land use and ecology-environment protection have been brought forward. These new trends and characters challenge greatly the prophase work of highway construction-highway survey and design. These years, exploration and research about the earth comes to a new era while the geotechnologies, especially 3S (GPS, RS, GIS) technologies, are advanced rapidly. Great progress in society, economy and technology is made with the combination or integration of 3S with other technology.Only studying and applying geotechnologies, making a breakthrough on the key issues, and improving traditional manner of highway survey and design can the characteristic of modern highway survey and design be fit, the demand of its construction be met, and sustaining development and spanning development of transportation be realized. Therefore, Research on the Key Issues in the New-style Highway Survey and Design Based on Geotechnology is timely and necessary, and the reality significance of this research is great.The paper aims at the characters of highway construction in the present age, researches on several significant key techniques, i.e. the three dimension high accuracy surveying of Ikonos satellite imagery with 1m resolution, the multi-temporal terrain transformation analysis in the active area of geological environment, and refining engineering quasi-geoid model and so on, and the new highway survey and design system with modern geotechnology based on the key technologies studied above. The research results have been applied successfully to the Mutuo Road construction in Mutuo county, Tibet, where it is the terrific area all over the world and no road county only in China. The mode of highway survey and design has been changed, and a significant breakthrough and innovation of means and method in highway survey and design have been made.The paper lucubrates in the theory and method of high accuracy survey of Ikonos satellite imagery. Ikonos is the first business satellite whose resolution is less than 1m in the world. Differing from others, the accuracy of this satellite imagery can satisfy the need of engineering. Ikonos imaging is line-scanning and forms stereo images along-track. The resolution of Ikonos imagery of panchromatic black and white is 1m, which is equal to an aerial photograph with a scale of 1:20,000. The rigorous sensor model isn't provided, but Rational PolynomialCoefficient (RPC) is substitute for benefit of Space Imaging and the convenience of application. At present, the most suitable general model for spatial transformation of high resolution imagery of Ikonos is rational function model. DLT transformation, affine transformation and polynomial transformation etc. are all different formation of rational function model. The practical research on spatial transformation of Ikonos stereo satellite images with rational function model in Mutuo, Tibet, shows that:(1) The accuracy of Ikonos satellite imagery reaches +0.800m with the first order rational function for spatial transformation when the PRC coefficients can not be gotten from vendor.(2) Without control points, the plane error of Ikonos stereo imagery is around 10m and its height error is less than 10m when the vendor's RPC coefficients are used.Ikonos satellite imagery can be affected by orbit error, attitude error, ephemeris error and coordinates datum, so that there are errors in image space. Based on the RPC, the geoposition precision of Ikonos stereo images can be improved evidently by added appended parameters. By block adjustments with parameters, the amount of field control points can be reduced. The practical research in Mutuo, Tibet, shows that:(1) There are both bias error and drift error in each Ikonos image. They are different from image to image, and the bias error is the main factor.(2) The accuracy is improved prominently by adding one control point in the image, and the control points can be distributed random. When there are two control points distributed in south-north direction in each Ikonos image, better precision can be gotten.(3) The precision of the Ikonos triangulation in Himalayas, Tibet, reaches: ±0.945m in plane, ±0.517m in height, ±1.076m in total, and ±0.3 pixels in RMS of image space.(4) When the interval of control points is 15km, the point RMS is around ±1.5m. When the interval is 20km, the point RMS is around ±2.0m. Interval of control points further, the accuracy of point worse.(5) The precision of DOM produced with Ikonos stereo images reaches ±0.70m, the precision of DEM reaches ±1.153m, the precision in plane, height and annotation of DLG reaches ±1.28m, ±1.14m, ±0.64m respectively. They all meet the demand for mapping with the scale of 1:2,000.The paper researches data terrain transformation analysis based on multi-source and multi-temporal roundly. Relative stabilization area in complicated geologic area has been found out so as to put forward a scientific, reasonable and economical project scheme for highway construction. By processed multi-temporal remote sensing data, Digital Elevation Model (DEM) and Digital Orthography Map (DOM) can be generated. The transform analysis of object on DEM is to analyse the differences between multi-temporal DEMs. The transform analysis on DOM uses the method of the sum of absolute value of gray difference and covariance of gray between multi-temporal DOMs to detect the changed area. The combined analysis based on DEM and DOM will improve the accuracy and reliability of results greatly. The research results of the terrain transform analysis with remote sensing data in 30 yearsinterval show that the production of combined analysis based on DEM and DOM is more accurate and reliable. It can satisfy the requirement of project. Not only the amount, size and scope of the terrain transformation, but also its trend and law can be found out when the terrain transformation associates with geological phenomenon such as mud-rock flow and landslip. Therefore, the valuable scheme can be put forward. The effect and power of geotechnology are more evident in engineering.The paper researches the theory and method of refining engineering quasi-geoid model. The refining engineering quasi-geoid model is the basis for realization of unitary surveying in plane and elevation. To meet the requirement of project, the relative accuracy of refining engineering quasi-geoid model should be under ±5cm, and its resolution should be l'x 1' at least. The refining engineering quasi-geoid model is related with the arithmetic and the quality, resolution, and precision of the data to be used. So, a gravity field model suited for local region should be selected, the gravity data measured in the ground and terrain data with high accuracy and high resolution should be adopted fully, and optimize arithmetic should be used. The l'x 1' refining engineering quasi-geoid model is formed by using gravity field model, terrain data and gravity data. The height anomaly is considered as the co-contribution one of earth gravity model, close region gravity anomaly and terrain correction, and vertical grads of full-Bouguer gravity anomaly. By using DQM2000B, l'xl' average gravity anomaly, l'x 1' terrain data calculated from Txl" digital terrain model, all possible gravimetric points, GPS-leveling points and some effective gravity points aboard, l'xl' refining engineering quasi-geoid model of Motuo, Tibet, is researched. The field check results show that the relative accuracy of this model reaches ± 2.5cm , the maximal error is not more than the twice of ±3cm which is the specification of height RMS in rule. The accuracy meets the fourth order leveling requirement of project in mountain area. It can replace leveling and be used for height control of the large scale mapping and engineering survey.On the basis of the study of 3D high accuracy survey of the high resolution satellite imagery, multi-temporal analysis of terrain transformation and refining engineering quasi-geoid model, a new highway survey and design system is researched and applied. While geotechnology is integrated into highway CAD, the integration, automation and visualization of highway survey and design are realized. A multi-scale route selection by terrain, geology and ecology-environment with computer assistant is come true, and the quality and technique of highway survey and design are improved.The research and application of the new-style highway survey and design system based on geotechnology in Mutuo Road, Tibet, show that:(1) The new system can acquire high accuracy data of terrain and geology rapidly for highway design, and the data gap of terrain and geology with large scale in Mutuo, Tibet, has been filled up.(2) 43km is shortened by route optimization, comparison and selection, and 1.1 billions yuan in this project is saved.(3) About 7,000 yuan per kilometer is saved and about 10 times of the total work efficiency is increased with the new system by comparing with traditional highway survey and design. The innovations of this paper are listed below:(1) A brand-new highway survey and design system with geotechnologies based on 3D high accuracy survey of high-resolution satellite imagery, multi-temporal terrain transform analysis and refining engineering quasi-geoid model by using GPS, RS and GIS technologies is formed(2)The theory and method of both spatial transformation with rational function model for the high-resolution satellite imagery and block adjustment with parameters are studied thoroughly. The practical research of lkonos-2 satellite imagery among large difficult area in China is for the first time. The accuracy of lkonos-2 imagery satisfies the requirement for mapping in difficult area with scale of 1:2,000.(3) A set of schemes for control distribution and triangulation of lkonos-2 satellite imagery are put forward, and the technique specification can be used to direct production of terrain digital data.(4) The terrain transform analysis based on multi-temporal data to find out relative stabilization area is researched for the first time in highway survey and design. With this method, the scheme of highway design can be the most optimum one.(5) VxV refining engineering quasi-geoid model is formed and applied for the first time in pratical project located at difficult area in Mutuo, Tibet. The relative accuracy of the model meets the fourth order leveling requirement of project in mountain area. Unitary surveying of plane and height is realized, and the separation of traditional survey in plane and height becomes history now.(6) The integration of geotechnology and advanced highway CAD is researched in a creative way, and multi-scale, integration, automatization and visualization of highway survey and design are realized.The new highway survey and design system based on modern geotechnology is advanced intechnology. Its economic benefit, society benefit and ecologic benefit are all prominent. It's arevolutionary breakthrough for the method and manner of highway survey and design.The theory and method in this paper will direct the highway survey and design of China in the21st century, and its research results are the examples of highway survey and design of Chinain the new era.In the subsequent work, the significant key technique and the brand-new system of highwaysurvey and design will still be undertaken test in practice. The method should be enriched,perfected and developed so as to accommodate the survey and design to different area anddifferent condition.