| Dispersion soil has special projects nature. One most typical nature is its resistanceability to erosion is quite low, in the low-salt-content water, especially in pure water, it willbecome scattered, and fine particles will be taken away by the flowing water. Manyengineering failure accident on water conservancy have been reported at home and abroad.Along with the social economy construction’s booming development, it has become more andmore common to build water conservancy project, road engineering and industrial and civilengineering construction in dispersion soil areas, earthquake, wind, wave, vehicle movementand the machine running will produce dynamic load. At present we have a lot of researchachievements on the identification and modification dispersion soil, but the study on itsdynamic characteristics is rarely to be reported, and to study the dynamic characteristicsfurther is very necessary. In order to know about its strength and deformation characteristicsunder dynamic loading more detail, to prevent it from some geotechnical engineeringdisasters and accident effectively, we design the experiment research project, to provide somebeneficial reference for engineering designing.DTC-199torsional dynamic triaxial apparatus has been used in this experiment study, wedesign the moisture content, dry density and confining pressure as three variables, whenfixing two of these parameters, to study the dynamic characteristics of dispersion soil under asingle variable factors influencing, and to analyze the relevant data, so we get the dynamicstrength curve and dynamic shear modulus-dynamic shear strain relationship curves ofdispersion soil under different test conditions, including calculating part dynamic strengthparameters, initial move shear modulus and maximum dynamic shear stress of test sample.And then, we can get some main conclusions concluding following:(1) When studying the dynamic strength characteristics of dispersion soil, we adopt axialstrain reaching5%as the standard of destruction for the experiment. According to thevibration times and the corresponding dynamic shear stress of destroyed test sample, we drawdynamic strength curves under different test conditions, and then find: As other conditions isthe same, the lower moisture content, greater dry density, higher confining pressure, thegreater dynamic strength, which is similar to dynamic strength properties of the loess.Through studying the normalization of the dynamic strength of dispersion soil we find that:The moisture content can influence it more, the higher moisture content of samples, thehigher normalization.(2) Dynamic strength of dispersion soil attenuates with the increase of number ofvibration, times of vibration has a significant impact on dynamic strength parameters timesthe role, its dynamic internal friction angle and dynamic stick together strength decreases withvibration times increases. When times is the same, dynamic internal friction angle anddynamic stick together strength change their values with the test conditions changing: The greater dry density, lower moisture content, the greater dynamic strength parameters value.(3) Through studying dynamic constitutive relation of dispersion soil we found: Therelationship of dynamic stress and strain is elliptic type, which is similar to Hardin-Drnevichhyperbolic model. Using test data, we can get the relationship curve of dynamic shear stressand shear strain under different test conditions, and find that the lower moisture content, thegreater its dynamic shear modulus; the greater dry density, the greater the dynamic shearmodulus; The higher confining pressure, the greater dynamic shear modulus.(4) Different experimental conditions influences the initial dynamic shear modulus andmaximum dynamic shear stress of dispersion soil much more. A study found that the greaterdry density, the lower moisture content, and its initial dynamic shear modulus will has greatervalue, which is the similar to the maximum dynamic shear stress. |
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