Abstract: Cylindrical specimens of =H=50 and 100 mm, dry density ρ=1.64, 1.74, 1.84 g/cm3, initial moisture content w=8.8%, 10.8%, 12.8%, were prepared by taking the expansive remolded mudstone with particle size smaller than 5mm in Chengde, Hebei province as the raw material. The axial expansion force Pax of the specimen and the circumferential expansion force Pcir were tested by the self-designed test equipment. The remolded mudstone specimens with =H=100 mm were soaked in alkaline simulated groundwater, acid simulated rainwater, and distilled water for 2 hours, and their Pax were tested; and the influence of specimen size, ρ, w and environmental water state on the Pax of remolded mudstone specimen was studied. Orthogonal method was used to analyze the sensitivity of ρ, w and environmental water state and pretreatment method to the influence of the axial and circumferential expansion forces of remolded mudstone specimen; and the variation rule of Pax and Pcir of the remolded mudstone specimen of the allowable micro-deformation rate Δ=0%, 1%, 2%, 3%, 4%, 5%, ρ=1.84 g/cm3, w=8.8%, =H=100 mm was studied. The results show that the Pax of =H=100 mm remolded mudstone specimens is 7.56% to 26.01% smaller than that of =H=50 mm. The Pax of specimens with two sizes decrease with the increase of w and increase with the increase of ρ; the Pax of the specimen soaked in alkaline simulated groundwater is 1.4~1.9 times larger than that of distilled water, while the Pax of the specimen soaked in acid simulated rainwater and Pcir is basically the same as the distilled water immersion; among the four factors, the pretreatment method is the main factor that affects Pax and Pcir. The more pre-disintegration times, the smaller the Pax and Pcir. The Pcir can be reduced by about 80% with 5% addition of cement; increasing Δ can effectively reduce the Pax and Pcir. When Δ is increased from 0% to 5%, the Pax and Pcir are reduced by 72.5% and 53.9% respectively.

Key words: road engineering, expansive remolded mudstone, orthogonal test, expansion force, micro deformation

摘要： 以河北省承德地区粒径小于5 mm的膨胀性泥岩重塑土为原材料，分别制备=H =50、100 mm，干密度ρ=1.64、1.74、1.84 g/cm3，初始含水率w =8.8%、10.8%、12.8%的圆柱体试件，采用自制的试验装置测试试件的轴向膨胀力Pax和环向膨胀力Pcir，并将=H=100 mm的试件分别经碱性模拟地下水、酸性模拟雨水、蒸馏水浸泡2 h，测试试件的Pax，研究了试件尺寸、ρ、w及环境水状态对泥岩重塑土Pax的影响规律；采用正交法分析了ρ、w、环境水状态和预处理方法4种因素对泥岩重塑土轴向与环向膨胀力影响的敏感性；研究了允许微变形率Δ=0%、1%、2%、3%、4%、5%，ρ=1.84 g/cm3，w=8.8%，尺寸为=H=100 mm试件的Pax及Pcir的变化规律。结果表明：=H=100 mm泥岩重塑土试件的Pax比=H=50 mm的小7.56%～26.01%，两种尺寸试件的Pax均随w的增加而降低、随ρ的增大而增大；经碱性模拟地下水浸泡的试件的Pax比经蒸馏水浸泡的大1.4~1.9倍，经酸性模拟雨水浸泡的试件的Pax及Pcir与经蒸馏水浸泡的基本一致；4种因素中，预处理方法是影响Pax及Pcir的主要因素，预崩解次数越多，Pax及Pcir越小，掺5%水泥，Pcir可减小约80%；提高Δ可有效降低Pax及Pcir，当Δ由0%提高到5%时，Pax及Pcir分别下降了72.5%与53.9%。

关键词: 道路工程, 膨胀性泥岩重塑土, 正交试验, 膨胀力, 微变形