## 2 Literature Review
### Risk of Cargo Liquefaction  
* Effect of moisture content  
There are many influencing factors for transportation accidents involving cargoes that may liquefy. It is necessary to identify and monitor the accident factors according to the mechanism of cargo liquefaction, the ship's stability, and the marine environment. [PERSON] [10] found that the actual moisture content of the cargo must not exceed the transportable moisture limit (TML) in order to prevent liquefaction. However, bauxite with an initial moisture content lower than the TML may still exceed the TML and liquefy due to changes in temperature and humidity during the transportation process. [PERSON] [11] found that observable indexes such as saturation and compactness can be used as key indexes to measure the degree of liquefaction. A higher moisture content or saturation increases the risk of liquefaction. The initial saturated or unsaturated state of cargo is disturbed by internal and external factors; thus, the actual moisture content of cargo exhibits temporal fluctuation. It is critical to avoid an increase in moisture content during the process of cargo production, storage, loading, and navigation of the ship [2]. In order to strengthen the control of moisture content in the loading and post-loading stages, [PERSON] [12; 13] proposed that biodegradable thermoplastic polymer material be added to the concentrate to absorb moisture from granular pores, thereby preventing slippage and transfer of concentrate during storage and transportation. [PERSON] [14] proposed that the application of suitable chemical filter aids in the filtration process of concentrate production could effectively reduce the water content of different mineral products to be 10%-15% lower than the TML. By reducing the initial moisture content of the cargo, the liquefaction resistance of the cargo during shipping can be improved.  
* Effect of weather or sea  
Heavy weather and adverse sea conditions are the main cause of many accidents involving Handy bauxite carriers. Once the impact of the external environment on the ship and cargo deteriorates into force majeure beyond the ship's disaster resistance [15], disaster eventually occurs. Therefore, special attention should also be paid to the complexity and variability of the environment of a sea route [16; 17]. Air humidity increases the risk of liquefaction and movement of highly absorbent solid bulk cargo [18]. Furthermore, seawater often sweeps over the ship deck in heavy weather conditions, resulting in water penetrating cargo holds, which may increase the cargo moisture content and affect the safety of the ship's operation. Moreover, wind affects the speed and rolling angle of the ship [19]. In the case of random waves, especially on heavy seas, ships roll at large angles, which can easily lead to capsizing [20; 21]. At the same time, ship rolling leads to cargo shifting. The initial shifting of cargo after liquefaction and the heeling moment of external wind and wave eventually lead to the ship capsizing [22]. Ship acceleration and kinematic waves affect cargo stability [23]. The hull vibration caused by rolling and machinery operation is not only harmful to the safety of the ship structure [24], but it can also change the characteristics of the cargo on board [25], even aggravating the liquefaction of cargo [26].