Study On Engineering Characteristics And Applicationg Of Basalt Fiber Modified Soil

In recent years,basalt fiber modified soil technology has been developed to a certain extent.Compared to traditional soil modification materials such as lime and cement,basalt fiber has significant advantages such as good soil compatibility,high continuous strength,and aging resistance.Based on the foundation soil improvement project of a fire station in southern Jiangsu Province,this paper selects typical fill samples from the project and conducts one-dimensional consolidation test,slow shear test,and consolidated quick shear test,Studied the basalt fiber content(0、0.25%、0.5%、0.75%)、The influence of basalt fiber length(6mm、15mm)on the consolidation and shear strength characteristics of basalt fiber modified soil.After that,based on the test results,the optimal mixing amount and optimal length of basalt fiber were selected and applied to the backfill improvement of the fire station project,and a comparison was made with the backfill effect of plain soil and lime soil around the engineering characteristics and economic performance.The main research results of this article are as follows:(1)Through one-dimensional consolidation tests,it was found that adding basalt fibers can accelerate the consolidation speed of soil,and both fiber content and fiber length have a certain impact on the consolidation characteristics of soil.When the fiber content is 0.5% and the fiber length is 15 mm,the two indexes of consolidation coefficient and compression coefficient of improved soil body improved the most significantly,consolidation speed of soil mass is accelerated obviously,the improvement of these two indexes is better under lower stress.(≤0.8MPa)(2)Through slow shear tests,it was found that the shear strength and expected bearing capacity of modified soil mixed with two lengths of fiber,6mm and 15 mm,had a certain degree of improvement.When the fiber content is 0.5% and the fiber length is 15 mm,the improvement effect of shear strength and expected bearing capacity is the best,with an improvement range of about 35%-45% compared to pure soil.(3)Through the consolidated quick shear test,it is found that the shear strength and expected bearing capacity of modified soil mixed with two lengths of fiber,6mm and 15 mm,have significantly improved.When the fiber content is 0.5%and the fiber length is 15 mm,the improvement effect of shear strength and expected bearing capacity is the best,and the improvement range is about 60%-80% compared to pure soil.(4)The optimal mixing amount of 0.5% and the optimal length of 15 mm basalt fiber obtained from the above tests are applied to the backfill improvement of the fire station project,Through the static penetration test,it was found that the average bearing capacity of 12% lime soil was the best,followed by 4% lime soil,basalt fiber modified soil was the third,and plain fill was the worst.However,the mixing of lime soil is not easy to be uniform,and the bearing capacity deviation is large.Basalt fiber modified soil has better uniformity and continuity.(5)Finally,through economic analysis of modified materials,it was found that using basalt fibers to improve the bearing capacity also significantly increased the cost,Basalt fiber modified soil currently has no advantages over lime soil.However,according to the future outlook for basalt fiber,its cost will continue to decrease as the production capacity increases.In the near future,considering its relatively uniform and continuous engineering characteristics,basalt fiber will be the preferred choice for soil modification in engineering.