Study On The Subgrade Of The Expressway Filled With Coal Gangue

The expressway, from Bengbu to Huainan, located in north-central region of AnhuiProvince, is an important part of the planning highway network of Anhui Province, Which isalso called Bengbu-Huangshan parallel lines in the four vertical and eight horizontalhighway network.The project, linking Beijing-Taiwan expressway and Huainan-Fu yang expressway, hasplayed the role of the second channel of Beijing-Taiwan expressway, and has effectivemitigation the traffic pressure of these expressways, communicating Hefei, Bengbu andHuainan, becoming the second high-speed channel Bengbu to Hefei. The construction of thisexpressway has an extremely important significance for the promotion of regional economicdevelopment.Quality is the top priority of the project construction. Therefore, this study combines theconstruction of the test section in the6th tenders of Bengbu-Huainan Expressway and indoorand field trials to determine the applicability of the subgrade of the expressway filled withcoal gangue, construction technology and quality control standards, which guide theengineering construction.By a large number of indoor and field trials, the coal gangue, as filler of the subgrade ofthe expressway, was studied deeply in material mechanical properties and construction qualitycontrol indicators, the main conclusions are as follows:1,The laboratory test results show that the natural coal gangue particles are goodgradation level, high dry density can be achieved by the fully compacted, the indicators, suchas bearing ratio, water absorption, the amount of expansion, crushing value, meet regulatoryrequirements of highway industry.2, The results of conventional rolling tests of different loose laying the thickness show:by increasing times of stamping, Settlement incremental decreases gradually, and deformationgradually stabilized; moreover, when the stamping reaches the certain number of times,stamping once more will produce springback deformation, and soil within a certain depthrange will be loose; analysis shows that this is consistent with the deformation characteristicsof the coal gangue;(3)additionally, using hydrostatic is effective.3, Stamping tests showed: stamping makes the soil below about40cm reinforcement, andresults topsoil loose; and, for the subgrade of Bengbu-Huainan Expressway filled with coalgangue, if using the layered roller compaction construction, the effect of stamping again is notvery good, but the stamping can be used as remedy measures,if the roller compaction is not dense; moreover, stamping will not cause significant edge clay to the lateral displacementand embankment stability no effect.4, Through the static pressure, vibration pressure and punching three ways Field Test, thefollowing conclusions can be obtained: for the subgrade of filled with coal gangue by roadbedlayered rolling construction, when loose laying completed, using vibration pressure cancomplete most of the compaction and subsidence, then using hydrostatic can be done tofurther settlement and deformation in order to achieve the required density; the subgrade offilled with coal gangue by roadbed layered rolling construction has dense gangue roadbed,without punching reinforcement.5, By indicators study of the rolling construction quality control, We have learned thatsedimentation rate, density and strike number of dynamic penetration, the three kinds ofindicators have its own advantages and disadvantages, and each of the indicators are notabsolute advantage. So the construction quality control should be integrated from multipleaspects.