Talus deposit is often seen in the hydropower projects in the southwest of China. Its mechanical properties are so complex that microscopic structure study is often used to reveal the essence of deformation and damage. The digital image processing technology (DIPT) is introduced to the discrete element simulation of talus deposits. Based on the study of DIPT, a Photo-To-PFC (PTP) automodeling program is developed. It is able to realize the whole process: analyzing and processing the digital image, acquiring the information and establishing the model files. The discrete element model of talus deposit can be established fast and correctly by the PTP from the digital photo on-site. A new way is opened up for the study of the talus deposit. As an example, some talus deposit data of Gushui hydropower station is used, structure model and mechanical properties of talus deposit are studied based on DIPT and PTP. The mechanical properties are studied by the numerical simulation of biaxial compression test. The results show that the gravels and soil mass compress with each other to form a corporate load-carrying body for sharing the external forces. The stress-strain curves show a strain-hardening stage obviously due to the impact of gravels. With the increasing of bond strength among soil particles, the initial elastic modulus and peak strength of talus deposit go up at a certain level; the initial elastic modulus and peak strength increase a lot as the existence of gravels.

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Talus deposit is often seen in the hydropower projects in the southwest of China. Its mechanical properties are so complex that microstructure study is often used to reveal the essence of deformation and damage. The digital image processing technology (DIPT) is introduced to the simulation of talus deposits. Based on the study of DIPT, a Photo-To-Flac3D (PTF) auto-modeling program is developed. It is able to realize the whole process: analyzing and processing the digital image, acquiring the information and establishing the micro-model files. A new modeling method is developed for the mechanical behavior simulation of talus deposit. As an example, some talus deposit data of Gushui hydropower station is used, the micro-model of talus deposit can be established fast and correctly by the PTF from the digital photo on-site. The mechanical properties are studied by the numerical simulation of triaxial test. The results show that the talus deposit has the feature of bully in deformation while that of Unicom band under force.

It takes on the technical and economic double benefits that fly ash taking the place of cement. However, water/binder of modern concrete is generally low; the research on the concrete performance which is based on large water/binder is no longer suitable for analysis of modern concrete. As to this problem, using different proportions of W/B and FA dosage as influencing factors, specimen is compounded for the compressive strength test. Then, mechanical properties of HPC are studied systematically. Based on this, macro-performance is analyzed from a micro-mechanism point of view through taking the electron micrograph. As the study shows, strength of HPC mixed with fly ash has low characteristics at early period while high ones at later period. At later hydration, fly ash effect plays a significant role, the growth rate of concrete strength increases as the increase of FA dosage. Compressive strength of concrete decreases as the increase of W/B and FA dosage. When the W/B is high, compressive strength is not sensitive to the change of W/B and FA dosage; but when the W/B decreases from 0.30 to 0.25, the concrete strength transition occurs. The influence of W/B on concrete compressive strength is more significant than that of the FA dosage; in the preparation of HPC, fly ash can be added more and cement is added less relatively by decreasing the W/B, displaying the role of micro-aggregate filling and modification, improving the strength and other performance of concrete. The study on micro-mechanism proves well the macro-phenomena above.