Internal mechanical losses in rocks of different genesis

The purpose of the study was to determine the mechanical loss coefficient Q-1 in rock samples of different genesis: sedimentary (limestone, dolomite), metamorphic (marble), magmatic (gabbro), and the dependence of this coefficient on frequency in the range from 0.003 to 0.1 Hz. This frequency range manifests itself in the form of seismic vibrations of the soil during earthquakes. They can lead to the destruction of buildings and other structures. Beam specimens with a width of 40 mm, height of 40 mm and length of 150 mm were used for testing. The ASIS test complex (NPO Geotek LLC, Penza, Russia) was the test basis. The test of the specimens used three-point scheme by the International Society for Rock Mechanics (ISRM) recommendations. The test device allows the minimisation of friction in the nodes of the setup. The ASIS software made it possible to set up a cyclic testing program with an indication of the number of cycles, the maximum and minimum deformations of the testing machine frame, and the speed of movements, with their increase and decrease. Two LVDT displacement transducers with a measure range of 10 mm registered deflection directly on the specimen. These converters had a connection to an 18-bit ADC of the QMBox measuring system (R-Technology, Moscow, Russia). The measuring system recorded the parameters, i.e., the resulting load on the sample, and the specimen deflection at the midpoint during deformation. The frame movement and the specimen deflection did not coincide with each other. Therefore, we took into consideration the displacements measured directly on the sample. The data set contains Q-1 test results for a few beam specimens, as well as the loss factors measured by hysteresis loop method. Frequency dependences and approximations of the Rayleigh attenuation model are also provided.本研究旨在测定不同成因岩石样品的机械损耗系数Q⁻¹，所涉岩石类型包括沉积岩（石灰岩、白云岩）、变质岩（大理岩）及火成岩（辉长岩），并探究该系数在0.003~0.1 Hz频率区间内的变化规律。该频率范围对应地震发生时土壤的振动频谱，此类振动可引发建（构）筑物的破坏。 本次测试采用尺寸为宽40 mm、高40 mm、长150 mm的梁状试样，测试平台选用俄罗斯奔萨NPO Geotek有限责任公司的ASIS测试系统。测试遵循国际岩石力学学会（International Society for Rock Mechanics, ISRM）推荐的三点弯曲试验方案，该装置可最大程度降低测试系统各节点处的摩擦损耗。ASIS配套软件支持循环测试程序配置，可显示循环次数、试验机机架的最大与最小变形量以及运动速度，并支持速度的增减调节。 本研究采用2台量程为10 mm的线性可变差动变压器（Linear Variable Differential Transformer, LVDT）位移传感器直接采集试样的挠度信号，该传感器连接至俄罗斯莫斯科R-Technology公司QMBox测量系统的18位模数转换器（Analog-to-Digital Converter, ADC）。该测量系统可记录试样所受总载荷以及变形过程中试样中点的挠度参数。由于试验机机架位移与试样挠度并不一致，因此需直接采用试样表面测得的位移数据。 本数据集包含多组梁状试样的Q⁻¹测试结果，以及通过磁滞回线法测得的损耗因子，同时还提供了频率依赖性数据以及瑞利衰减模型的拟合结果。