Application Of High-pressure Grouting In Treatment Of Large-thickness Fill Site

In recent years,with the rapid development of China's economy,infrastructure construction has also made considerable progress,the western development and "Belt and Road" is to promote the construction of the climax of the northwest.China has a large number of construction projects,and most of these projects are located in mountain or fill ditch from the ground.The filling in the filling area is mainly rock block and filling soil,and some construction waste is mixed in.In the process of filling,except the surface was rolled by transport vehicles,most of the fill was not compacted in any form,and was basically a natural deposit,forming a large thickness of fill.Lanzhou Tian Yu Phoenix City project is a typical representative of this kind of digging mountain.The site was originally a hilly gully landform with a large undulating landform.In the middle of the site,there was a large gully running nearly east-west.The width of the gully mouth was about 85 meters.After manual excavation and filling,the landfill became a gently sloping construction site with an elevation of 1648.89-1655.70 meters,the general trend is higher in the northeast and lower in the south and west.Division of Mountain Gully geomorphology from geomorphologic unit.The main backfilling materials are collapsible plain backfill and broken rock block produced by mountain excavation.The plain fill is mainly loess-like silty soil,and the broken rock block is mainly sandstone and argillaceous sandstone.In this paper,the treatment of the whole filling site in Phoenix City,Tianyu,Lanzhou,is taken as the research object,and the physical and mechanical properties of Red Sandstone are studied in depth,in this paper,it is added to red sandstone by high pressure grouting together with cement,and a reasonable and effective red sandstone improvement scheme is put forward.The related research results are of great significance to improve the engineering properties of Red Sandstone,which can provide reference for the improvement of backfilling of such red sandstone in the future.The main contents are as follows:(1)The physical and mechanical properties such as collapsibility and compressibility of the original filling site are deeply understood through the previous geological prospecting report.Provide basis for site improvement.(2)Through grouting test in zone 1 and zone 2,the improvement of the physical and mechanical properties of the whole filling layer after grouting is analyzed.(3)Through the comparison of geological prospecting data before and after grouting,the advantages and disadvantages of high-pressure grouting in dealing with large-thickness filling sites are analyzed.