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Yunnan is one of the largest centres of genetic ecological diversity and the richest area for elite germplasm of rice (O. sativaL.) resources in the world. Its indigenous rice average diversity index of six ecological groups are, in turn, javanica(1.2319) > aman(1.1738) > communis(1.1726) > nuda(1.1618) > aus(1.1371) > boro(0.9889), and there are great differences between indica(1.1454) and japonica(1.2081). The indigenous rice in Yunnan can be divided into 58 varieties, almost the total number found in China, and the cultivars account for 8.6% of the total cultivars in China. A great difference in ecological diversity index of rice resources between prefectures or counties in Yunnan province also exists, with the southwest part (Lincang, Xishuangbanna, Dehong, Simao) and southeast part (Wenshan) having been found to be the largest centre of genetic diversity, as their average genetic diversity index ranges from 1.2735 to 1.2036, especially. The average diversity index of the Cangyuan, Gengma, Zhenkang, Yongde, Yingjiang, Jinghong, Menghai, Shuangjiang, Ruili, Longchuan, Mojiang, Wenshan and Guangnan counties, in particular, have an average diversity index ranging from 0.8 to1.0. On the contrary, in Diqing, Dongchuan, Kunming, Lijiang, Qujing, Chuxiong, it is comparatively low, i.e., 0.7843–1.1075. Differences in the ecological diversity index of rice resources between rice regions are small, only 1.1322 to 1.2849.

In the process of shield machine tunneling, the interaction between cutter head and soil is very complex. In order to meet the requirements of tunneling, the cutter head was designed according to the construction conditions of Tianjin metro and the Archimedes spiral layout method. The granite model and cutter head model were respectively established by the ABAQUS. The granite model was based on the classic Drucker - Pragel model, and the failure criterion including element deletion function was employ to simulate the yield and failure of rock. The force of the cutter head under cutting condition was analyzed. The results show that the maximum equivalent stress of the cutter head is 8.216950 MPa, and the allowable stress of the cutter head material is 230 MPa, which was less than the allowable stress of the cutter head. The results indicated that the cutter head can meet the actual work requirements and has high structural reliability. The research process of cutter head arrangement provides a method for solving practical engineering problems, and the numerical simulation results provide a reference for the design of cutter head.