Rock soil mass dynamic parameter damping ratio spot test device and method

Abstract

The invention discloses a rock soil mass dynamic parameter damping ratio spot test device and method. The device comprises a sparker electrode, a high voltage control unit, a sensor capable of controlling the directions, a control and data acquisition instrument, and a computer. The test method comprises the steps that firstly hole drilling is conducted in a test site, the holes include a vibration hole and two test holes, the vibration hole and the test holes are on the same section, the vibration hole is provided with a sparker, a speed sensor capable of controlling the directions is set up in the test holes; the amplitude-frequency relation of the seismic wave is obtained by performing a Fourier transform of the time domain data from two groups of sensors through the sensor, the data acquisition instrument and the computer testing and recording the vibration information of the same survey line with different distances from the quake source; the relation of the phase-and-frequency of the test point vibrations is obtained though conducting a correlation analysis of two groups of data from the sensors; and finally the damping ratios of the rock and soil layers corresponding to different frequency vibrations are calculated, according to the vibration of every test point and the relation between the damping ratio and the test points and the relation between the damping ratio and the distances to the quake source.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering testing, in particular to an on-site testing device for dynamic parameter damping ratio of rock and soil mass, and also relates to an on-site testing method for damping ratio. Background technique [0002] Damping ratio is one of the dynamic parameters of rock and soil, and plays an important role in seismic design. At present, the methods of testing the damping ratio of rock and soil mainly include indoor test and field test. Indoor tests include (soil) dynamic triaxial tests, (soil) resonance column tests, (rock) cantilever beam tests, etc.; field tests are mainly on-site precast concrete block excitation tests. For rock and soil, there are some insurmountable problems in the above test methods. First of all, it is difficult to sample and prepare samples for indoor testing. It is inevitable to disturb the soil structure during soil sampling and sample processing. In particular, the undi...

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Problems solved by technology

For rock and soil, there are some insurmountable problems in the above test methods.

First of all, it is difficult to sample and prepare samples for indoor testing. It is inevitable to disturb the soil structure during soil sampling and sample processing. In particular, the undisturbed soil is basically not obtained during sampling, and even the final processed sample itself is a remodeled body. , the results of indoor tests with non-original specimens certainly cannot reflect the real state of the soil on site; the rock cantilever beam test requires the test object to be a complete rock block, but the actual rock mass contains a large number of discontinuous surfaces such as joints and fissures. The mechanical properties of the body are very different and cannot be substituted for each other.

Secondly, the cost of on-site vibration tests is high, and usually only a small amount of tests can be carried out on a certain exposed rock and soil layer, and it is impossible to carry out vibration tests on rock and soil layers below the surface, and the test results cannot represent the entire stratum

Third, the test results contain little information. The damping ratio is a parameter reflecting the energy loss of the stress wave in the process of propagating in the rock and soil body. It is related to the frequency of the stress wave. The current test methods cannot provide the relationship between the damping ratio and the frequency.

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