APPLICATION OF QUICKLIME-LIMESTONE POWDER-WSS SOIL STABILIZER IN ROAD REGENERATION OF DRILLING WASTE MUD

On the basis of three issues,namely,the high moisture content,the high plasticity index and the poor construction performance of the waste drilling mud,this paper aims to design and select the quicklime and limestone powder as pretreatment agent materials. We conducted a series of tests in the laboratory. The effect of modification was characterized by the dehydration speed,variation range of Atterberg Limits,particle state as well as degree of crushing difficulty. Thereafter,we used the unconfined compressive strength(q_u),water stability coefficient(γ_w),California bearing ratio(CBR) and the compressive modulus of resilience(E_c) as indices to determine the optimal ratio of waste soil,quicklime,limestone powder and WSS. These materials are selected to make modified compaction soil used in construction of roads. After that,we studied the influence of the aggregate size on the strength,broken shape and water stability. The results show that pretreatment can effectively reduce the moisture content of the waste soil,increase the drying rate,improve the Atterberg Limits and enhance the mixing effect with the powdered curing agent. The performance of quicklime-limestone powder-WSS(QLW) is far better than the cement. Pretreatment can not only improve the construction performance of the soil,but also promote the curing effect. In addition,the test clarified that with the decrease of D_max,the strength and water stability of the QLW solidified soil gradually increased,and the failure mode changes from brittle shear failure to plastic compression failure.