Soilbags are expandable three-dimensional geosynthetic bags made from high-density polyethylene or polypropylene. This study conducted a series of plate load tests to explore the bearing capacity of soft foundations reinforced by soilbags filled with solid wastes based on an onshore wind farm project in China. The effect of contained material on the bearing capacity of the soilbag-reinforced foundation was investigated during the field tests. The experimental studies indicated that soilbag reinforcement with reused solid wastes could substantially improve the bearing capacity of soft foundations under vertical loading conditions. Solid wastes like excavated soil or brick slag residues were found to be suitable as contained material, and the soilbags with plain soil mixed with brick slag had higher bearing capacity than those with pure plain soil. The earth pressure analysis indicated that stress diffusion occurred through the soilbag layers to reduce the load transferred to the underlying soft soil. The stress diffusion angle of soilbag reinforcement obtained from the tests was approximately 38°. In addition, combining soilbag reinforcement with bottom sludge permeable treatment was an effective foundation reinforcement method, which required fewer soilbag layers due to its relatively high permeability. Furthermore, soilbags are considered sustainable construction materials with advantages such as high construction efficiency, low cost, easy reclamation and environmental friendliness while making full use of local solid wastes.

Frost heave damage problems in canal linings are a common phenomenon in seasonally frozen ground regions. These problems are regarded as interactions between heat transport and moisture flow processes. To research the influence of frost heave prevention in two types of canal structures in the Ningxia irrigation district of China, a two-dimensional coupled heat transport and moisture flow model was used to analyze temperature characteristics in the traditional canal lining structure and a new type of canal lining structure for frost heave prevention. The simulated results from this numerical model are in agreement with in situ temperature measurements for both canal lining structures. The in situ measurement results show that the new canal lining structure exhibits low seepage, low thermal conductivity, quick drainage speed and less uneven deformation. Therefore, this new canal lining structure is a good choice for frost heave prevention in seasonally frozen ground regions.

This paper introduces a new method to prevent frost heave in cold regions using soilbags (bags filled with soils). The mechanism of the proposed treatment method is introduced. A number of tests of soilbag frost heave, thawing settlement and strength were conducted in the laboratory on soilbags filled with soils. The results showed that soilbags exhibit less frost heave and thawing settlement than soils for the same conditions. In addition, the strength of soilbags was not affected by increasing the number of freeze–thaw cycles. These findings indicate that soilbags can not only prevent frost heave but also inhibit capillary water and film water migration through soilbags.

In the Middle Route of the South-to-North Water Transfers Project,cement is used to modify the engineering characteristics of expansive soil,and the quality of the stabilized expansive soil depends on the cement content,therefore it is important to ensure the accuracy of detecting the cement content.EDTA(Ethylene Diamine Tetra Acetic Acid Disodium Salt) titration method is used to detect the cement content;however,age effects occur using this method.In this paper,expansive soil samples obtained from Nanyang area were mixed with different cement contents and then titrated using the EDTA method after they were stored for different time periods,which can help understand the age effects of the stabilized soil on the EDTA titration in detecting the cement content.The problems and solutions of using the EDTA titration method in detecting the cement content of the stabilized expansive soil in the Middle Route of the South-to-North Water Diversion Project were discussed.The experiment results showed that the effective calcium content decreases significantly and the detected cement content using the EDTA titration method may be lower than the actual value when the storage time is longer than 2h and the cement content is not less than 4%.In this case,the standard curve of EDTA consumption with time or the decay curve of the effective calcium content should be used to correct the detected value to ensure the accuracy of the conclusions.