Based on the effective stress principle, indoor model tests were conducted in this study to calculate buoyancy of an underground structure and determine law pore water pressure conduction silty clay strata. A comprehensive structure-water-soil interaction test system was established with four-in-one features: Elimination lateral friction, controllable head, circulating supply drainage, simulation groundwater flow. Four- seven-gradient continuous monitoring completed using fine sand clay,...

An experimental apparatus is described for the investigation of frequency dispersion, and related attenuation, fluid-saturated rocks under confining pressure undrained boundary conditions. The forced-oscillation method performed on cylindrical samples. measurement stress strain hydrostatic oscillations allows dynamic bulk modulus to be inferred, while axial give access Young's Poisson's ratio. We present calibration measurements dispersion attenuation standard materials such as glass,...

Abstract Quantitatively assessing attenuation and dispersion of elastic‐wave velocities in partially saturated reservoir is difficult because its sensitivity to fluid distribution. We conducted experiments on homogeneous Indiana limestone samples, by two methods: drying imbibition which lead different distribution for a given saturation. Forced oscillations (from 0.004 100 Hz) ultrasonic (1 MHz) measurements were done under confining pressure measure the change elastic moduli with frequency...

We built a broad-frequency-band measurement system for rock elastic parameters based on the stress-strain method following Batzle et al., Geophysics 71, N1–N9 (2006). The gives strain amplitude anomalies at some frequencies. These put limitations range of frequency and jeopardize credibility results over broad band. To overcome these limitations, we investigated cause anomalous strains by numerical model simulations with finite element experimental apparatus. Through systematic analysis...

Abstract The variation of the seismic properties with frequency a brine‐saturated sandstone sample porosity 22% was measured using forced oscillation apparatus. Two pairs orthogonal biaxial strain gauges were pasted at different locations length center sample. In range 1–300 Hz, these two gauges, we observed experimentally same global flow but local flows (squirt flow). Therefore, observation is influenced by position in contrast to flow. Indeed, strongly microstructure (structure grain...

SUMMARY Based on both forced oscillation and ultrasonic pulse transmission methods, we investigated solid pore infill influences rock elastic moduli in a broad frequency range $[ {1 - 3000,\,\,{{10}^6}} ]$ Hz for different differential pressures. For Berea sandstone sample, filled sequentially by (${22\,\,^{\rm{o}}}{\rm{C}}$), quasi-solid (${26\,\,^{\rm{o}}}{\rm{C}}$) liquid (${34\,\,^{\rm{o}}}{\rm{C}}$) octadecane, frequency-dependence was found the Poisson's ratio, Young's modulus bulk...

SUMMARY In fully fluid-saturated rocks, two common phenomena are documented both experimentally and theoretically for frequency-dependent elastic moduli attenuation, that is, the drained/undrained transition relaxed/unrelaxed transition. When investigating these transitions with forced oscillation method in laboratory, it is crucial to consider boundary differences between laboratory underground. A 1-D poroelastic numerical model was previously established describe their effects; however,...

SUMMARY We conducted stress–strain oscillation experiments on dry and partially oil-saturated Fontainebleau sandstone samples over the 1–2000 Hz band at different confining pressures to investigate wave-induced fluid flow (WIFF) mesoscopic microscopic scales their interaction. Three tested rock have similar porosity between 6 7 per cent were saturated degrees with oils. The measurement results exhibit a single or two attenuation peaks that are affected by saturation degree, oil viscosity...

SUMMARY Elastic moduli and velocities of tight sandstones are strongly influenced by rock-frame heterogeneity, pore microstructure fluid in addition to pressure probing-wave frequency. The effects frequency on the elastic different from those conventional with high porosity permeability due complexity microstructure. To investigate these effects, we measured two sandstone samples for their dry saturation conditions using ultrasonic transmission technique low-frequency stress–strain method....

The effect of temperature on the dynamic parameters silty clay in a seasonally frozen region was assessed using GDS triaxial test system. strength parameters, elastic modulus, damping ratio, and other soil samples were analyzed under different conditions. results demonstrated that shear (internal friction angle cohesion) load increased significantly with decreasing temperature, internal sharply below 0 °C. modulus as decreased changed ice-water phase change region. slope stress-strain curve...

ABSTRACT Seismic waves passing through partially saturated porous rocks produce pressure gradients in the fluid phase, and, hence, resulting flow is accompanied by various length scales. The major mechanism responsible for seismic attenuation and dispersion arguably known as wave‐induced between inhomogeneities of microscopic, mesoscopic macroscopic Previous studies have revealed that differentiating influence heterogeneities at scales on wave within exploration sonic frequencies,...

SUMMARY Understanding the effects of pressure and rock microstructure on seismic elastic properties fully saturated rocks is considerable importance in a range geophysical applications, especially at frequency range. A recently proposed theoretical model squirt attenuation dispersion can be used to interpret stress dependence basis triple porosity structure. The poroelastic requires knowledge variety pore parameters, particular, compliant pores with discrete distribution aspect ratio. We...

Using the stress–strain oscillation method, we conducted experiments on a sandstone over frequency range of 1–100 Hz at differential pressure 5 MPa to investigate effects oil saturation and oil/water substitution modulus dispersion attenuation. We first saturated with low viscosity (2#) different degrees, then replaced 2# more viscous (68#) finally injected distilled water in oil-saturated sample. Young's modulus, Poisson's ratio extensional attenuation were measured during these processes....

SUMMARY The forced oscillation method is widely used to investigate intrinsic seismic wave dispersion and attenuation in rock samples by measuring their dynamic stress–strain response. However, using strain gauges locally measure the strains on surfaces can result errors determining moduli of rocks with mesoscopic scale heterogeneities. In this study, we developed a 3-D numerical model based Biot's poroelastic theory effect gauge location, number size response wave-induced fluid flow. Our...

Based on the effective stress principle, indoor model tests were conducted in this study to calculate buoyancy of an underground structure and determine law pore water pressure conduction silty clay strata. A comprehensive structure-water-soil interaction test system was established with four-in-one features: Elimination lateral friction, controllable head, circulating supply drainage, simulation groundwater flow. Four- seven-gradient continuous monitoring completed using fine sand clay,...

In this paper, By using a large common ABAQUS finite element software to simulate hospital,s deep foundation pit excavation process in Changchun, Contrasting respectively pile-anchor retaining structure which had been adopted the project with pile-strut bracing structure. Obtaining stress and deformation of soil pile under two supporting types, Analysis types feature only from perspective force piles, To provide reference for future support work.