Search

Embankments filled with disintegrated carbonaceous mudstone (DCM) are prone to uneven settlements because of water-softening property and secondary disintegration of carbonaceous mudstone. To address this problem, nano-Al2O3 and cement were proposed in this study to improve the strength of DCM. Many nano-Al2O3- and cement-modified DCM (NACDCM) specimens with various nano-Al2O3 contents were prepared. Unconfined compression tests and triaxial compression tests were performed to examine the strengths of NACDCM under different conditions. Moreover, X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM) observations were performed to reveal the microscopic mechanism for modification of the NACDCM. Macroscopic results showed that the unconfined compressive strength of NACDCM reached maximum when the nano-Al2O3 content was 0.2%. The cohesion showed positive correlation with nano-Al2O3 content while the angle of internal friction presented negative correlation with nano-Al2O3 content. Moreover, microscopic results indicated that nano-Al2O3 and cement improved the strength of NACDCM, mainly through cement hydration reaction, pozzolanic reaction, ion exchange, gel effect and filling effect.

To investigate the influence of confining pressures and temperatures on the seepage characteristics of fractured rocks, seepage tests were conducted on a fractured silty mudstone using a self-developed experimental system, and the effects of different factors on coefficient of permeability were discussed. The results showed that the increasing confining pressure will gradually decrease the coefficient of permeability, and this process is divided into two stages: 1) the fast decrease stage, which corresponds to a confining pressure less than 30 kPa, and 2) the slow decrease stage, which corresponds to a confining pressure larger than 30 kPa. Unlike confining pressure, an increase in temperature will increase the coefficient of permeability. It is noted that fracture surface roughness will also affect the variation of coefficient of permeability to a certain extent. Among the three examined factors, the effect of confining pressure increases is dominant on fracture permeability coefficient. The relationship between the confining pressure and coefficient of permeability can be quantified by an exponential function.

To study the mechanical characteristics of the disintegrated carbonaceous mudstone (DCM), consolidated drained triaxial tests were conducted on the DCM with three degrees of compaction (i.e., 90%, 93%, and 96%). Then, the nonlinear constitutive model suitable for the DCM was established based on test results using a logarithmic function. The stress-strain characteristics of the DCM were analyzed. The results revealed that the axial strain of the DCM was positively correlated with the deviatoric stress and lateral strain. The slopes of deviatoric stress-axial strain curves decreased with the increase of axial strain and so did the slopes of the axial strain-volumetric strain curves. The strength of the DCM increased with the increase of the confining pressure and the degree of compaction. In addition, the axial strain induced by dilatancy was also positively correlated with the degree of compaction and the confining pressure. Furthermore, under triaxial loading conditions, the relationship between the stress and strain of the DCM can be expressed by a logarithmic function; based on this, a nonlinear constitutive model with ten material parameters was derived. In addition, the results of numerical tests using the model showed similar stress-strain characteristics of the DCM comparing with the triaxial tests. Hence, it indicated that the nonlinear constitutive model based on the logarithmic function can reflect the nonlinear stress-strain characteristics of the DCM.

The similarity model test is one of the important means to study the engineering properties of soft rock. This study aims to develop similar materials for silty mudstone, which has characteristics of low strength and water expansion, based on traditional materials including gypsum, barite powder, clay minerals, and distilled water. The orthogonal design method was used to determine the mixing ratios of the similar materials. The density, uniaxial compressive strength, tensile strength, elastic modulus, and Poisson’s ratio were selected as control indicators of the similar materials. The results show that the water content is the dominant factor for the density, tensile strength, elastic modulus, and Poisson’s ratio of the similar materials of silty mudstone, while the gypsum content is the dominant factor for the uniaxial compressive strength. The physical and mechanical properties of the similar material samples with water content of 19%, barite powder ratio of 32%, and gypsum mass of 250 g show good similarity to those of the raw silty mudstone. The water absorption and expansibility of similar materials with clay mineral ratio of 12% are consistent with those of the raw silty mudstone. The scanning electron microscopy (SEM) observation indicates that the similar material with optimal mixing ratios exhibits a similar microstructure to that of silty mudstone.

BACKGROUND Fatigue is one of the most common subjective symptom,due to lack of objective diagnostic criteria ,it is often neglected,especially in the early stage of disease.It is very important to establish an objective evaluation method for diagnosis of disease fatigue and non-disease fatigue based on tongue and pulse data. Our research team has been engaged in the informatization and intelligentization research of TCM diagnosis technology for more than 30 years, we have been engaged in health evaluation and analysis of large clinical sample data for many years, and accumulated a certain amount of typical data,in this area of research, foundation of our work has outstanding advantages. OBJECTIVE The purposes of this study is to explore a new method for clinical diagnosis of fatigue, by analyzing the characteristic of objective tongue and pulse data of disease fatigue subjects and sub-health fatigue subjects, and establishing the diagnosis and classification models of sub-health fatigue and disease fatigue based on the tongue and pulse data. METHODS In this study,736 subjects were selected from the Physical Examination Center, and were divided into healthy control, sub-health fatigue group and disease fatigue group according to physical examination indexes and health status assessment criteria. TFDA-1 tongue diagnosis instrument and PDA-1 pulse diagnosis instrument independently developed were used to collect the tongue image and sphygmogram of the subjects. Multivariate statistical analysis methods were usded to analyze the tongue and pulse data distribution pattern of the fatigue subjects, and machine learning methods were used to establish the diagnostic classification models of fatigue. RESULTS The tongue feature TB-a,TB-b,TB-H,TB-S,TB-I,TB-Cb,TC-L,TC-H,TC-I,TC-Y,TC-Cr,TC-Cb,perAll and perPart were statistically significant different among three groups (P < 0.05, P < 0.01). The sphygmogram feature t1,t4,h5,W1,W2,W1/t and W2/t showed statistically significant differences among three groups (P < 0.05, P < 0.01). There was a canonical correlation between the tongue and pulse data in the disease fatigue group, and the correlation coefficient was 0.649 (P CONCLUSIONS Sub-health fatigue and disease fatigue subjects had different tongue and pulse characteristic. Diagnosis and classification models can be established using basic information, tongue and pulse data to explore a new method for evaluating fatigue state.