中型动三轴仪研制及微小应变测试技术应用

常规土工三轴仪测试精度较低.为提高试验精度,引进微小应变测试技术,即在三轴压力室增设内置力、局部位移和非接触位移等测试装置,研制了中型动三轴仪.这不仅可以排除试样端垫误差,而且使试验精度提高了1个数量级,即轴向应变接近10-6.用该三轴仪,并综合运用力控和位移控制方法进行了动剪切模量和阻尼比试验.试验结果证明,该三轴仪具有精度高、性能稳定及操作简便等优点,可用于研究各种粗粒土的动力特性.

Development of medium scale dynamic triaxial apparatus and application of small strain measurement technique

The test precision of conventional triaxial apparatus is lower. A medium scale dynamic triaxial apparatus was made for increasing the precision. In this apparatus, the small strain test technique was adopted by installing devices called inner force transducer, local displacement transducer and gap sensor in the pressure cell. As a result, the bedding error was eliminated, and the test precision was increased by one order of magnitude; in other words, the axial strain can be measured at 10~(-6). Applying force control and displacement control, a series of dynamic shear modulus and damping ratio tests were conducted by means of the triaxial apparatus. The results indicate that the triaxial apparatus has the advantages of high precision, steady capability and being easy to operate. It can be used for the research on dynamic properties of coarse-grained soils.