## 6 Conclusions  
In this study, a new total soil thrust assessment method for a grouser-attached off-road tracked vehicle was proposed based on the block-shaped failure mechanism [5; 6; 7; 8; 9; 10]. The following conclusions were obtained.  
1. Attaching the grouser increases the total soil thrust at a specific slip ratio and improves tractive performance of the off-road tracked vehicle. This is because the grouser converts the shear between the material of the track and the soil into shear between the soils and generates additional soil thrust on the side of the track (i.e., side thrust).
2. The total soil thrust-slip ratio relationship of the off-road tracked vehicle differed between the existing method and the proposed method significantly. The existing method showed a greater maximum soil thrust at a lower slip rate than the proposed method. When the soil shows a hardening behavior, the total soil thrust in the existing method is always greater than that in the proposed method. When the soil shows softening behavior or hump behavior, the total soil thrust predicted by the existing method is greater than that calculated by the proposed method until a specific slip ratio, after which the latter becomes greater.
3. The existing method does not consider the difference in soil thrusts with shape ratio (that is, change in the grouser spacing) under the same grouser height. In contrast, the soil thrust calculated using the proposed method differed not only according to the height of the grouser but also according to the shape ratio. As the grouser height increases and the shape ratio decreases (i.e., the grouser spacing decreased), the total soil thrust of the off-road tracked vehicle increases significantly. However, when the grouser aspect ratio was 7.5, the increase in the total soil thrust realized by longer grousers is smaller.  
The results of this study are expected to be useful for evaluating the tractive performance of a grouser-attached off-road tracked vehicle. With the proposed method, the soil thrust of a continuous track can be properly predicted considering the independent shearing of soil blocks at the soil-track interface demonstrated in recent experimental works [5; 6; 7; 8; 9; 10]. However, it should be noted that the total soil thrust assessment method proposed in this study follows the scope of previous studies [5; 6; 7; 8; 9; 10]. Caution should be exercised when assessing the soil thrust on different types of soil (e.g., cohesive soil or highly compressible soils) whose shearing characteristics are completely different from those of granular soil or mixed soil. Also, the soil beneath tracks for high-speed operations is subject to a dynamic load; the soil thrust may be developed in different ways. Further experimental work performed under various operating conditions is necessary to validate the outcomes of this study, including full scale testing.  
Conceptualization, S.-H.B.; methodology, S.-H.B.; validation, T.B. and J.C.; formal analysis, G.-B.S.; investigation, S.-H.B. and G.-B.S.; writing--original draft preparation, S.-H.B.; writing--review and editing, G.-B.S. and T.B.; visualization, S.-H.B. and G.-B.S.; supervision, T.B.; funding acquisition, J.C. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was conducted with the support of the \"National R&D Project for Smart Construction Technology (No. 22 SMIP-A158708-03)\" funded by the Korea Agency for Infrastructure Technology Advancement under the Ministry of Land, Infrastructure and Transport, and managed by the Korea Expressway Corporation.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Acknowledgments:** Construction Engineering Research Institute at Hankyong National University provided research facilities for this work.  
**Conflicts of Interest:** The authors declare no conflict of interest.