Paleotectonic residual strain energy in Southwest China

Based on the orthotropic elastic theory of rock masses, the X-ray method was used to measure the distribution of macro-residual strain energy density along a depth profile,using core samples taken from 47 large-aperture deep boreholes in four regions of Southwest China： the Longmenshan, Anninghe, Honghe, and Xianshuihe fault zones.Then, the vertical gradients of the macro-residual strain energy density and the macroresidual strain energy contained in high-energy cuboid block segments along each fault zone were determined. The results demonstrate that the macro-residual strain energy stored at shallow levels in the rock mass in these fault zones may be partly responsible for generating many large earthquakes and may explain why the large earthquakes in this region are typically shallow.

Present three-dimensional crustal deformation in Hainan Island

Hainan Island,located at the southeast edge of the Eurasian Plate,is affected by the motion of multiple plates,with its northeast edge mainly dilatating and its western margin presently compressing. By analyzing the GPS rates during 1999- 2007 in Hainan and its adjacent region,we determined horizontal movement rates of 3. 0-21. 1 mm /a at the west of 104°E,evidently affected by the Indian Plate extrusion.Their directions are SE-SN-SW from east to west and are separated by the main fault. The principal strains have the same characteristics. The stations east of 104°E move mainly in the SEE direction. The eastward rates are 2. 1-8. 5 mm /a and northward rates are 0. 4- 2. 7 mm /a. The GPS rates during 2009- 2013 show that stations at the edge of the island move SEE relative to the Eurasian Plate,with rates relative to the mean benchmark,indicating that there are small relative movements between stations,whereas QION station,located in the middle,moves in the NW direction at a greater rate. Vertical differential movement is apparent in the northeast zone of the island. Upwelling of mantle plume material possibly influences the local stress.Three-dimensional GPS rates indicate that,at present,inherited crustal movement is dominant in Hainan.

Effects of vertical electric field and compressive strain on electronic properties of bilayer ZrS2

Using first-principles calculations,including Grimme D2 method for van der Waals interactions,we investigate the tuning electronic properties of bilayer zirconium disulfides（ZrS_2/ subjected to vertical electric field and normal compressive strain.The band gap of ZrS_2 bilayer can be flexibly tuned by vertical external electric field.Due to the Stark effect,at critical electric fields about 1.4 V/？,semiconducting-metallic transition presents.In addition,our results also demonstrated that the compressive strain has an important impact on the electronic properties of ZrS_2 bilayer sheet.The widely tunable band gaps confirm possibilities for its applications in electronics and optoelectronics.

Theoretical elastoplastic analysis for foundations with geosynthetic-encased columns

As a new technique in ground improvement, geosynthetic-encased columns (GECs) have promising applications in soft soil foundation. By assuming yielding occurs in the columns while the surrounding soil and the geosynthetic remain elastic, an elastoplastic analytical procedure for foundations improved by GECs is proposed. The radial stresses that the geosynthetic provides and the elastoplastic deformations of the foundation resting on a rigid base are derived. A comparison with finite element analysis shows that the proposed method is effective and can provide a reasonable prediction of a GEC's deformation. Subsequent parametric analysis indicates that higher geosynthetic stiffness leads to better performance of the composite foundation. The optimum length of encasement is related to the load acting on the foundation and the permissible vertical and radial displacements of the column. Moreover, as the dilation angle of the column increases, the settlement decreases, especially under high loading. The influence of the encasement is more significant in soils with smaller elastic modulus.