Research On Filling Technology Of Freeway Roadbed At The Cavity Area Of Lava In Hainan Province

The reason of the cavity of lava area is,when volcano erupting, ejected magmaflowing along the surface,and the magma cooling solidification and magmatic gascontinues to escape or centralized,belonging to the primary structure. The cavity oflava area is an unfavorable geological body, has causing more and more attention byroad builders about the high-grade highway roadbed construction. This article takethe Hainan Haikou to Tunchang freeway as the relying project in Hai’nan province,several aspects had considered on researching the technology of subgrade filled at thecavity of lava area.First of all,geological mapping the cavity of lava area,analysising on the reasonof the cavity of lava area,and also putting forward the method of the engineeringgeological investigation and classification.Throug the density test,acoustic wavetest,resistivity test,study the volcano rock’s physical properties;using the uniaxialcompressive strength test,uniaxial compressive deformation test and splitting strengthtest,study on volcano rock’s mechanical properties under the dry and saturatestate,and also study the influence of the compressive strength,cohesion and internalfriction which caused by porosity.Secondly,through the method of radar and high density electrical and seismicimaging,comparative study on the applicability at the area of lava when detecting.Theresults showed that the method of geological radar is effective.Using the insitu plateloading test,study the bearing capacity and deformation modulus at the honeycombtype cavity of lava.Finally,compared the effect on the grouting method and pouring concrete pilemethod, find that pour concrete pile can obtain better treatment effect.On the basis ofthese,study the subgrade filling technology and method at the cavity of lava area,anduse the high density resistivity method for the detection and evaluation.The results show that the subgrade construction technology and method differentfrom the other areas,and need deal with method of detection,foundationtreatment,construction techniques particularly at the cavity area of lava,for ensuringthe stability of subgrade and pavement which constructed.This study have somecertain reference value at the cavity area of lava when we construct on it.