Suggested New Statistical Parameter for Estimating Joint Roughness Coefficient considering the Shear Direction

The 10 standard roughness joint profiles provided a visual comparison to get the joint roughness coefficient (JRC) of rock joint surface, but the accuracy of this method is influenced by human factors. Therefore, many researchers try to evaluate the roughness morphology of joint surface through the statistical parameter method. However, JRC obtained from most of the existing statistical parameters did not reflect the directional property of joint surface. Considering the 10 standard profiles as models of different roughness joints, we proposed a new idea for the accurate estimation of JRC. Based on the concept of area difference, the average of positive area difference (Sa) and sum of positive area difference (Ss) were first proposed to reflect the roughness of joint surfaces on the basis of directional property, and their fitting relationship with JRC was also investigated. The result showed that the Sa and Ss calculated by shearing from right to left (FRTL) and JRC backcalculated from right to left (FRTL) came to a satisfying power law. The correlation between JRC and Sa was better than that of Ss. The deviation between the predicted value calculated by Sa and the true value was smaller than that obtained from the existing statistical parameters. Therefore, Sa was recommended as a new statistical parameter to predict the JRC value of joint profile. As the sampling interval increased from 0.5 to 4 mm, the correlation between Sa and JRC gradually decreased, and the accuracy of the prediction results also declined. Compared with the single JRC values for joint profiles mentioned in the literature, the forward and reverse JRC were obtained. Based on the laboratory direct shear test of the natural joint surface, the JRC values of two joint surfaces in four shear directions were backcalculated by the JRC-JCS model. Based on 3D scanning and point cloud data processing technology, JRC of joint surface in different directions were obtained by Sa method, and they are very close to those obtained by JRC-JCS model. It is confirmed that Sa could accurately estimate the joint roughness coefficient and reflect its anisotropy.

Anisotropic Variation Characteristics of Pore Distribution Based on Saturated Clay Microstructure

The pore characteristics of saturated clay sourced from microstructure pictures in Pearl River Delta region of south China is analyzed considering the microstructure in different sample sections. The histogram statistics are compared with each other by pore data in terms of the size, the shape and the arrangement of link status. The repercussions of including the anisotropy ratio law of pore characteristics are focused to study saturated clay. It is found that the analysis considering anisotropy ratio results in consolidation by pore distribution based on saturated clay microstructure. The soil porosity of horizontal section was larger than that of vertical section. Vertical section status induced the directional property, and it would be presented directional probability entropy which is able to calculating the chaos of overall arrangement which is a lower value because of directional property.

Microstructure Distribution of Soft Clay under Conditions of Stratigraphic Profiling Variation

Base on the microscopic structure is characterized by anisotropy of microstructure that inherent in the process of saturated soft clay with sedimentary primary anisotropy or external force caused by induced anisotropy, biological changes along with the trend of the minimum potential energy. By studying the spindle rotation stress characteristics of the soil of the microscopic distribution, the pore characteristics of saturated clay sourced from microstructure pictures in Pearl River Delta region of south China is analyzed considering the microstructure in different stress conditions. Microstructure distribution of soft clay under conditions of section profiling variation including the anisotropy ratio law of pore characteristics are focused to study saturated clay. It is found that major-minor axis status induced the directional property of saturated soil in the process of consolidation by vacuum preloading. And porosity shapes factors which are small indicate directional property would be probability entropy which is able to calculating the chaos of overall arrangement, and it will be a lower value because of directional property. It is apparently inconsistent with the pore distribution of saturated clay which results from the cut section of different point of angle. And horizontal joint and large pore space constitute one of the saturated clay structure characteristic, which related to different pressures.