The Experimental Research Of Improved Weakly Consolidated Sand Filler’s Pavement Performance

Transportation as the basic business of Western Development of China needs to further promote,and highway,railway and other infrastructure projects relate to the great cause closely,but Lanzhou as the transportation hub in the Northwest is a typical area of Weakly consolidated sandstone.If weakly consolidated sandstone filler can be used for subgrade construction project,it will have important economic,environmental and social benefits.My article takes the Lanzhou area’s weakly consolidated sandstone as the research object,and carries out the system research on engineering properties through four aspects which are base on investigating information,determining sample,testing sample which is improved by using cement,and numerical simulation analysis.The laboratory experiment of expansibility and disintegration are used to discuss the expansive and disintegrative mechanism of weakly consolidated sandstone;Through a series of laboratory experiment to research the physical and mechanical performance of the weakly consolidated sandstone filler and the pavement performance of weakly consolidated sand filler which is improved by cement.The numerical simulation is used to analyze the Subgrade model’s settlement deformation,which is under the different conditions of filler by using the ANSYS software.And we acquire some valuable research results.(1)The weakly consolidated sandstone has swelling and disintegration characteristics,if it can take the reasonable construction technology to make weakly consolidated sandstone mechanical disruption in advance,and until the rock’s collapse tends to the steady state,at the same time to control the water content strictlily for that to avoid weakly consolidated sandstone takes place greater expansion deformation,we propose to make weakly consolidated sand filler act as railway subgrade filler under the premise will have great research value.(2)Through the Results which acquires by testing the physical and mechanical properties of weakly consolidated sandstone filler we can find that: The mechanical properties of unimproved weakly consolidated sandstone filler does not meet the technical requirements for railway subgrade filler,so it can not be used to subgrade filling directly.(3)The experimental result of weakly consolidated sand filler’s pavement performance which is improved by different ratio of cement show that cement can improve performance obviously such as packing compression performance,mechanical properties,bearing capacity and so on;With the ratio of cement modified mixture more than 6% that can meet railway subgrade filler’s technology requirements,and have enough safety stock,so when considering the economic benefits,we advice to make 6% as the best fit ratio of cement improved weakly consolidated sand filler.(4)The subgrade is fillied with weakly consolidated sandstone filler which is improvedby different ratio of cement is made as the research object,and numerical simulation analysis is carried out on the subgrade settlement deformation of the subgrade model which is affected synthetically by the subgrade gravity and the upper static load by using the ANSYS software,and the analysis results fully verify the feasibility of 6% as the best fit ratio of cement improved weakly consolidated sandstone filler.