A study of the insulating and anti-frost heave effects of polystyrene boards under molded bag concrete conditions

In this study, the channel frost heaving actions in the Hetao irrigation area of Inner Mongolia were examined and a field in-situ test platform was established. Then, experimental investigations were conducted regarding the insulating and anti-freeze effects of polystyrene boards under the conditions of concrete bags with different thicknesses. In this study's experiments, concrete bags with different thicknesses were set, along with a test block of polystyrene boards with different thicknesses. The research results showed that by adding 2–5 cm molded bags, the total accumulated temperature increased in the range of 3.93–9.22% and the frost heave rate decreased by between 18.28 and 55.44% concrete, on the basis of 10 cm molded bag concrete. In addition, when 4–8 cm polystyrene boards were laid, the total accumulated temperature increased by 207.63–272.25%, and the frost heave rate decreased by between 71.43 and 96.6%. The absolute slope of the curve fitting of the frost heave rates and the soil temperatures decreased by 44.6–58.7%. HIGHLIGHT The results show that, the biggest bending moment of channel slope is in the 1/3 of canal slope, the biggest shear is in the toe of slope, the biggest bending moment of canal bottom is in the 1/2 of the Canal bottom. According to the judgment of Typical Channel, frost heaving damage will occur on the slope and bottom of the South Branch Canal without taking insulation measures.

Comprehensive Assessment of Water Quality and Pollution Source Apportionment in Wuliangsuhai Lake, Inner Mongolia, China

Water quality is a key indicator of human health. Wuliangsuhai Lake plays an important role in maintaining the ecological balance of the region, protecting the local species diversity and maintaining agricultural development. However, it is also facing a greater risk of water quality deterioration. The 24 water quality factors that this study focused on were analyzed in water samples collected during the irrigation period and non-irrigation period from 19 different sites in Wuliangsuhai Lake, Inner Mongolia, China. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were conducted to evaluate complex water quality data and to explore the sources of pollution. The results showed that, during the irrigation period, sites in the middle part of the lake (clusters 1 and 3) had higher pollution levels due to receiving most of the agricultural and some industrial wastewater from the Hetao irrigation area. During the non-irrigation period, the distribution of the comprehensive pollution index was the opposite of that seen during the irrigation period, and the degree of pollutant index was reduced significantly. Thus, run-off from the Hetao irrigation area is likely to be the main source of pollution.

A Study of the Insulation Mechanism and Anti-Frost Heave Effects of Polystyrene Boards in Seasonal Frozen Soil

The damages resulting from frost heaving are the main causes of channel destruction in seasonal frozen soil regions. Over the years, many experimental studies have been performed regarding the channel anti-frost heaving in the Hetao irrigation area. However, there have been few experimental research studies conducted regarding the insulation and anti-frost heave effects of polystyrene boards (EPS) of different thicknesses. Therefore, in order to explore the insulation mechanism and anti-frost heave effects of precast EPS laid under the conditions of different thicknesses, an anti-frost heave test field was established in the Hetao irrigation area for the examination of the ground temperatures, frozen depths, frost heave amounts, and water content change rules. This study’s results showed that, for the laid EPS with thicknesses between 2 and 12 cm, the frost-heave reduction rate ranged from 53.2% to 92.6%; total accumulated temperature warming ranged from 248.65% to 565.93%; and the frozen depth reduction rate was between 59.8% and 75.9%. It was determined that the EPS per cm additions could effectively improve the ground temperatures at a buried depth of 30 cm by 0.78 °C, and reduce the frozen depth by 10.1 cm. Then, by comprehensively considering the positive economic and insulation effects, it was determined that the most appropriate thickness of the EPS laid under the precast concrete slabs in the Hetao irrigation area of Inner Mongolia was 8–10 cm.

Discussion on Moisture Migration and Law of Frost Heave of Seasonal Frozen Soil in Hetao Irrigation Area, Inner Mongolia

Hetao irrigation area in Inner Mongolia is one of the four major irrigation areas in China, seasonal frozen soil is widely distributed in this area. Irrigation channel engineering experiences seriously freeze-thaw cycle many times in the long winter, its maintenance is the important and difficult point all long in irrigation channel engineering of Hetao irrigation area. For this, we analyze the moisture migration and law of frost heave characteristics of seasonal frozen soil in Hetao irrigation area.