# Controlling Conditions of the One-Dimensional Consolidation Test on Peat Soil
## 1 Introduction  
Peat soil is a loose, water-rich accumulation that us formed from organic matter that has been deposited in swamp lakes after plant death [1] and accounts for \(\sim\)5-8% of the total area of the Earth [2]. In China, 64% of peat is distributed in the Sichuan, Anhui, Heilongjiang, and Yunnan provinces [3]. The content of organic matter in peat soil is generally more than 10%, with some having an organic matter content as high as 98%. According to the Code for Investigation of Geotechnical Engineering (GB 50021-2001) [4], soil with an organic matter content of more than 60% is peat, and soil with an organic matter content that is more than 10% and less than or equal to 60% is peaty soil. According to the organic matter content (\(W_{u}\)), peat soil can be further divided into low organic peat soil (10% \(<Wu\leq\) 25%), medium organic peaty soil (25% \(<Wu\leq\) 40%), and highly organic peaty soil (40% \(<Wu\leq\) 60%). Peat soil features a high water content, a large pore ratio, high compressibility, low strength, strong rheology, and compressibility that is 5-20 times higher than that of common soft clay [5, 6]. A peat soil foundation can encounter several problems, such as a large amount of settlement and long settlement times [7]. For example, an embankment on a peat soil foundation in Canada has more than 7 m of settlement [8]. A highway in Miyazaki County, Japan, that is built on a foundation with a peat soil layer has more than 11 m, of settlement, as measured over four years [9]. After five years of operation, the accumulated settlement of the peat soil foundation under an expressway in Yunnan Province is 1.3 m, and settlement is still rapidly developing. Because of the long settlement time and large deformations that can occur to peat soil foundations, researchers have studied the consolidation characteristics of peat soil [10, 11, 12]. Whiles studying this process, it was found that temperature [13; 14], stress conditions, and the over consolidation ratio influence the consolidation characteristics of peat soil [15; 16]. [PERSON] et al. [17] studied the deformation difference of peat soil in the range of 15-65 \({}^{\circ}\)C for every temperature increase of 10 \({}^{\circ}\)C. The results show that the consolidation deformation of peat soil increases when the temperature increases. [PERSON] and [PERSON] (1996) compared the results of consolidation tests that were conducted at 24 \({}^{\circ}\)C and 35 \({}^{\circ}\)C and observed that the secondary consolidation coefficient of peat soil has a positive correlation with the temperature during testing. The creep temperature coefficient was first proposed by [PERSON] and has shown to be able to modify the secondary consolidation coefficient. [PERSON] et al. [13], [PERSON] and [PERSON] [14], and [PERSON] and [PERSON] [18] considered the results and conclusions from previous studies of the effect of temperature on the consolidation characteristics of peat soil, so the ambient temperature is controlled at about 20 \({}^{\circ}\)C in their research. Due to the rich organic matter in peat soil, microorganisms propagate rapidly, and biological oxidation (mainly including humification and mineralization) occurs in an oxygen rich environment, which leads to changes in the soil structure and properties [19]. [PERSON] [20] studied two peatlands in California and Florida and suggested that 80% of the subsidence in peatlands in a hot and humid climate is due to the biological oxidation of aerobic bacteria. [PERSON] [21] analyzed the carbon pool level of peatland, and [PERSON] et al. [22] analyzed the change process of amino acids in peatland, which proved that the contact between peatland and air accelerated the decomposition of the organic matter that was present in the peat soil. [PERSON] et al. [13] found that the decomposition of peat soil is accelerated when it is consolidated in air and proposed that a 1% thymol solution should be used to control the decomposition of organic matter during consolidation tests. [PERSON] et al.