Study On The Compaction Test Features Of The Loess Layers In Xinfeng City And Luochuan County

Loess is widely distributed in our country, and one of the main problems of the highwayin loess areas is the subsidence and deformation of loess subgrade. The core of its resolutionis to improve the compaction density of loess subgrade. Therefore, whether the loess subgradecan be up to the standard compaction is particularly important. There are many factorsinfluencing the compaction, but what really has controlling effect can be generally dividedinto internal factors (granulometric composition, microstructure) and external factors(specificmoisture content, compacting power efficiency).In this paper, the loess layers of Kong jia yuan in Qingyang city of Longdong (east ofLiupan Mountain), and that of Shi jia zhuang village in Luochuan county locating in the loessplateau gully region of the Weibei district was chosen as the object of this study. Throughmore than twenty people spending nine months of field visits, field sampling, laboratory soiltesting, standard heavy compaction tests, theoretical analysis, etc, the loess layers of the twoareas was analysed from stratigraphic profiles, optimum moisture content and maximum drydensity. In comparison of the compaction test features of loess stratigraphy along the verticaldirection in the two representative areas, conclusions were drawn as follows.1．In different loess areas, from the west to the east, the change rules of the best moisturecontent scope of the layers was not obvious, and the range of maximum dry density increasedgradually.2．In different loess areas, from the west to the east, the weighted optimum moisturecontent of the loess layer is approximately, but the weighted maximum dry density graduallydecreased; meanwhile, the weighted best moisture content and maximum dry density of theancient loess were both gradually increased.3．The maximum dry density and best moisture content of Potou loess is bigger thanothers, the maximum dry density and best moisture content of Malan loess、Lishi loess andWucheng loess is approximately.4．The maximum dry density and best moisture content of the two different loess layersin different geologic times Q4、Q3、Q2、Q1are compared and analysed. Because of the loss of Q4layer and Q1layer of Kong jia yuan village, its study cann’t be producted. As to loess indifferent districts, the best moisture content in Q3and Q2are both gradually increased fromwest to east, while the maximum dry density gradually decreased.5．In the one loess areas, the weighted optimum moisture and the weighted maximumdry density of the loess layer and the ancient loess is approximately.6．In different loess districts, best moisture content decreases gradually, while themaximum dry density gradually increases from west to east.