Slope failure disasters have been increasing in recent years, and although research on heavy rains and earthquakes that cause them is progressing, it is difficult to investigate the deformation mechanism inside slope that is the predisposing factor. Therefore, in order to deal with slope disasters, it is a agenda to evaluate complicated gravitational deformation mechanism inside the slope.

Firstly, We confirmed that the balanced cross-section method can evaluate gravitational deformation mechanism inside a dangerous slope. Secondly, we developed a new finite element method （BaFEM） as a numerical analysis method that can reproduce the balanced cross-section method quickly and universally. In the balanced cross-section method, large deformation accompanied by displacement and separation of strata occurs. For this reason, it is difficult to replicate the balanced cross-section method with the previous finite element method. Therefore, we improved the previous finite element method and proposed a new method of creating and deleting contact elements repeatedly by separating the elements from a certain distance. And, complex gravitational deformed slope such as buckling and toppling, which cause slippage and separation, can be replicated, and the stress and share strain inside the slope during large deformation can be evaluated moment by moment.

As a result, it is possible to predict not only the deformation mechanism but also the future deformation in the reproduction analysis of the actual gravitational deformation slope using BaFEM.

The author has proposed the following chemical weathering index （CWI, abbreviated name Sueoka’s Index） as an index that enables the degree of chemical weathering and the chemical weathering direction to be quantitatively evaluated simultaneously for granitic residual soils that are found throughout the world.

CWI = [Al₂O₃ + Fe₂O₃ + TiO₂ + H₂O(±)(mol%)/Total chemical components (mol%)]×100（％）

In this Report （Part 1）, the chemical weathering index CWI is used to clarify composition in accordance with the combination of the chemical components based on the mobility of the chemical components, and the significance and effectiveness of the CWI and its meaning for today’s issues are discussed. From the results it is shown that the extent and direction of chemical weathering of granitic residual soils can be quantitatively expressed using both the CWI value and the position in triangular coordinates of the three chemical component groups of which the CWI is composed.

In addition, using the CWI, definitions have been established for terminology related to weathering products, such as weathered granite, Masado （decomposed granite soil）, saprolite, and lateritic soils, laterite, and geomechanical classification of residual soil grounds incorporating rock mass classification have been established.

Recent experiments in the field of rock mechanics have seen an increase in the type of measured properties and a rise in the complexity of experimental setups, particularly in the shape of jackets. Using 3D printer to fabricate jackets would eliminate the inconvenience of taking sensor cables out of the jacket. In the last few years, rubber resins have been developed and used for stereolithography 3D printer. This allows a high printing accuracy to be achieved and complex three-dimensional shapes to be printed. These have a high printing accuracy and can be used to print complicated three-dimensional shapes. In this study, we attempted to fabricate a jacket using a 3D printer with a hard-rubber resin and evaluate its sealing ability for permeability and mechanical tests of rocks. The results of the leakage test indicated that the pore pressure did not change even when the confining pressure was increased to 20 MPa, demonstrating that the jacket seal was complete. In addition, the performance of the resin was evaluated, and the rubber was found to be sufficiently capable when utilised as a jacket for permeability and mechanical tests when water was used as the confining pressure medium.