191 results about "Effective stress" patented technology

The invention discloses a fluid-solid coupling numerical simulation method and device based on an embedded discrete fracture model. A structured grid is adopted to divide a reservoir matrix, and a discrete fracture model is embedded to construct an oil and gas reservoir geological grid. Establishing a transmission function, and formulating a porous medium fluid seepage control equation according to the transmission function. The equation is solved at each time node, a pore pressure field is obtained, and an equivalent pore pressure field is obtained through weighted averaging and serves as a boundary condition of the solid mechanical control equation. Expanding an oil and gas reservoir geological grid model, combining a crack-rock constitutive model, an effective stress principle and a stress balance equation, constructing a solid mechanical control equation, and solving and simulating rock deformation by adopting a finite element method and a Newton-Rafson method. Based on the constitutive relation of the composite material, matrix and crack seepage attributes are updated, the interaction between a seepage field and a stress field is considered in an iterative coupling mode, and multi-field coupling simulation is achieved. The problem that an existing method cannot be applied to a real oil and gas reservoir is solved.

A pore pressure prediction method for fine-grained hybrid sedimentary rock based on variable P-wave velocity includes: carrying out a P-wave velocity test of rock under different effective stresses, determining a function form of the relationship between acoustic velocity and effective stress, fitting the parameters in the function by optimization, and establishing an evaluation model of effective stress influence term by lithology. According to the measured formation pressure data and the effective stress influence term model, the acoustic velocity background value is deduced, the logging curve is preferred, and the acoustic velocity background value logging evaluation model is established. According to the logging curves of DT and DEN, combined with the lithology identification results, the acoustic velocity background value is calculated, and then the effective stress of the formation is obtained, and then the pore pressure is determined according to the overburden pressure.

The invention relates to a concrete temperature-stress two-parameter cooperative monitoring and early warning method and system, and belongs to the technical field of concrete structure health monitoring, and the method comprises the steps: activating a composite sensor network disposed at a preset position of a concrete structure, and executing a sensor self-calibration mode; the method comprises the following steps: synchronously acquiring temperature and stress original monitoring data of each node, processing based on an altitude air pressure compensation algorithm, and outputting a temperature gradient field matrix and a stress tensor sequence with aligned time domains; the method comprises the following steps: separately calculating a thermal stress component and an effective stress component, performing integral calculation on hydration reactivity, generating a multi-dimensional feature vector set, inputting a pre-constructed prediction model, executing time sequence evolution prediction, calculating a crack probability value, performing environment correction in combination with real-time environment parameters, outputting a risk level identifier, and matching a preset regulation and control strategy. And generating an equipment control instruction set and executing corresponding regulation and control actions. According to the invention, the accuracy and timeliness of crack risk prediction can be improved.

The invention discloses a settlement prediction system based on soft soil creep, which relates to the technical field of settlement prediction, and dynamically calculates stress increment, total stress increment and pore water pressure by collecting the loading rate and underground water level change of a foundation in real time, and further calculates vertical effective stress based on the intermediate variables. Therefore, an accurate void ratio calculation formula is constructed. The systematized process not only improves the precision of settlement prediction, but also enhances the adaptability of the model to the change of actual working conditions. Specifically, through collection and processing of real-time data, the method can quickly respond to changes of foundation conditions, and it is ensured that model parameters are always in the optimal state. Calculating the void ratio by using the initial model parameters and evaluating the difference between a predicted value and an actual observed value in combination with an error function, so as to realize iterative optimization of the initial model parameters and finally obtain a corrected empirical model. The robustness and reliability of the model are remarkably improved, and settlement prediction is more accurate and reliable.

The invention discloses a three-dimensional crustal stress field visualization construction method under a complex geological structure condition, and relates to the technical field of crustal stress field analysis. Comprising the following steps: in a to-be-analyzed area, obtaining characteristic data such as density and Poisson ratio of a surface rock-soil layer, a sedimentary layer, a parent material layer and a bedrock layer through well drilling; applying seismic waves, acquiring longitudinal wave and transverse wave speeds of each rock-soil layer by using a geophone, and calculating a shear modulus and a bulk modulus; and establishing a finite element model to analyze the strain tensor under the load, and calculating the stress tensor in combination with the modulus. Calculating pore water pressure, and correcting the stress tensor to obtain effective stress. Fault feature information is obtained through a geological report, and the stress tensor is further corrected to obtain accurate and effective stress. And constructing a three-dimensional geologic model and dividing grids, mapping accurate and effective stress to each grid unit, and completing visual construction of the crustal stress field by utilizing visual software. Safety and economic benefits are effectively improved, and risks caused by geological factors are reduced.

Systems, methods, and apparatus for characterizing reservoirs are discussed. As an example, a method for characterizing a reservoir is discussed that includes determining a ki parameter, a αE parameter, and a αP parameter based at least in part on the at least four pairs of effective stress and permeability; and predicting a hydrocarbon production rate from reservoir represented by the sample rock based at least in part on the ki parameter, the αE parameter, and the αP parameter.

The invention discloses a ground subsidence monitoring system under the condition of ultra-large water level drawdown, and relates to the technical field of foundation pit dewatering, a seepage field change analysis module arranged on the system can analyze the movement process of underground water in a soil body of a foundation pit wall according to water body state data monitored in real time and in combination with the saturation state and permeability of the soil body, and the seepage field change analysis module can analyze the movement process of underground water in the soil body of the foundation pit wall through the module. The system can automatically perform hierarchical division on the soil body in the foundation pit wall, obtain the spatial and temporal distribution of the water head of each soil layer in the precipitation process, make the subsequent stress analysis and settlement evaluation more accurate, and accurately calculate the effective stress change of the soil body in the precipitation process based on the spatial and temporal distribution of the water head of each soil layer. And the additional stress influence of the settlement of the upper layer soil layer on the lower layer soil layer is analyzed, so that the settlement volume of each layer of soil body is obtained, and the stress and settlement monitoring based on stratified analysis enables the system to carry out detailed evaluation on differential settlement and interlayer stress change, so that the risk of structural instability caused by settlement difference is effectively prevented.

The invention relates to the technical field of rock-soil stress monitoring, in particular to a rock-soil stress monitoring data analysis method and system. The method comprises the following steps: acquiring geological data and construction design data of a river bridge construction area, and analyzing piling immersed tube distribution difference to obtain piling immersed tube distribution difference data; performing extrusion lateral stress deflection simulation according to the piling immersed tube distribution difference data, further estimating stress transfer loss to obtain effective stress transfer data, and performing stress impact structure instability analysis between adjacent rocks and soil; and constructing a rock-soil stress risk monitoring model based on a random forest algorithm, and sending the model to a terminal for rock-soil stress monitoring data analysis. The rock-soil stress monitoring technology is optimized, so that the rock-soil stress monitoring technology is more accurate.

The invention discloses a double-row medium-length hole blasting method for a filling stope. According to the method, a theoretical value range of each blasting parameter is deduced according to field engineering practice, an ore rock blasting crushing mechanism and a blasting parameter theoretical formula. The method comprises the following steps of: constructing a stope blasting model with different hole bottom distances, explosive unit consumption and resistance line combinations by using ANSYS numerical simulation software in combination with physical and mechanical properties of ore rocks and field explosive performance parameters, and preferably selecting double-row medium-length hole blasting parameters according to a chamber effective stress distribution rule and a roof area vibration velocity peak value of the ANSYS blasting model. According to the method, by selecting the double-row optimal medium-length hole blasting parameters, it is guaranteed that ore rocks in the chamber are fully crushed, the effective stress invading the roof and the blasting vibration velocity peak value are reduced, and the roof is prevented from being damaged. And meanwhile, the explosive loading amount is reduced, the economic cost is reduced, and the production efficiency of a mine is improved.

The invention provides a concrete elastic-plastic damage constitutive model construction method and system, belongs to the field of computers, and solves the problems that in the prior art, an integral or gradient enhanced regularization method is adopted to establish a non-local constitutive model, but the two methods require relatively fine finite element grid division, and numerical value implementation is very difficult. Comprising the following steps: 1, determining a damage variable, nominal stress, effective stress and an elastic-plastic damage stress-strain relationship, and decomposing the effective stress according to tension and compression characteristics; 2, in the effective stress space, a concrete elastic-plastic damage constitutive model is established; and step 3, based on an energy regularization method, determining a tensile damage variable, a compression damage variable and a corresponding stress-strain relationship, and in combination with a plastic loading and unloading rule, constructing a concrete elastic-plastic damage constitutive model based on energy regularization. The invention provides the construction method of the PC box girder concrete elastic-plastic damage constitutive model under the non-uniform constraint, and the application range is wide.

The invention discloses a geotechnical engineering catastrophe dynamic real-time intelligent early warning method and system based on displacement monitoring, and the method comprises the steps: collecting the real-time displacement data and related parameters of a geotechnical engineering region through displacement monitoring equipment, and transmitting the real-time displacement data and related parameters to a bank slope stability evolution analysis platform to establish a multi-dimensional database; calling a fractured rock mass effective stress analysis model to calculate rock mass effective stress distribution characteristics, and inputting a multi-grid sliding surface stress calculation algorithm to obtain a potential sliding surface stress state and a critical threshold value; inputting the sliding surface stress parameters and the displacement data into a multi-field coupling analysis learning prediction model to obtain a displacement evolution trend and a catastrophe risk coefficient; and finally, real-time early warning information is generated and fed back through the catastrophe dynamic real-time intelligent early warning module. The method improves the real-time performance and accuracy of early warning, can effectively guarantee the safety of geotechnical engineering, and is suitable for catastrophe early warning scenes of geotechnical engineering such as bank slopes and foundation pits.

The invention discloses an invasion limit surrounding rock excavation method for a large deformation section of soft rock, and relates to the technical field of invasion limit surrounding rock excavation construction for the large deformation section of the soft rock. The invasion limit surrounding rock excavation method for the large deformation section of the soft rock comprises the steps that refined partitioning of an invasion limit body is achieved through dense scanning and loose circle testing; dividing the invasion limiting body into a core pressure-bearing area and a peripheral stress relaxation area; a main stress diversion arch crossing an invasion limit section is constructed through full-ring radial grouting reinforcement and erection of a strong profile steel temporary cover arch, and effective stress transfer is achieved; the mode of subarea gradual type dismantling and chiseling and instant supporting is adopted, a peripheral stress relaxation area is treated firstly, then a core pressure-bearing area is treated, and surrounding rock disturbance is reduced; the circumferential stress equalization is realized by compensating grouting in stages and dynamically adjusting the grouting pressure according to real-time monitoring data. According to the method, the excavation construction safety of the invasion limit surrounding rock of the large deformation section of the soft rock can be improved, surrounding rock disturbance is reduced, stress distribution is optimized, and the treatment efficiency of the invasion limit surrounding rock is improved.

The invention relates to the technical field of data processing, discloses a coupling calculation method for seepage deformation analysis of a dam body-dam foundation of a high earth and rockfill dam, and aims at solving the problem that a data acquisition method of an existing terminal device is poor in accuracy and safety. Carrying out grid division on a solid domain and a reservoir water external flow field area; performing transient calculation on the reservoir water external flow field area based on a computational fluid mechanics method, and solving an RANS equation to obtain flow field evolution data of the reservoir water external flow field area; the pressure field is applied to the surfaces of the dam body and the dam foundation, seepage-deformation coupling calculation is conducted on a solid domain based on a Biot equation in a u-p form, and displacement fields, pore pressure fields and effective stress fields of the dam body and the dam foundation are obtained; and post-processing the calculation result, and extracting response features. The accuracy of high earth and rockfill dam body-dam foundation seepage deformation analysis coupling calculation is improved, and the method is particularly suitable for high earth and rockfill dams with dam foundation defects.

The invention relates to a plugging layer three-hole three-seepage well circumference effective stress calculation method and system, and the method comprises the steps: collecting a reservoir rock core, and obtaining rock matrix mechanical characteristic parameters through triaxial compression; the method comprises the following steps: collecting a reservoir core and on-site drilling fluid, firstly, obtaining physical and chemical parameters of interaction between a rock aperture and the drilling fluid through a pressure transfer experiment, then, testing physical and chemical parameters of interaction between a rock fracture fluid and the drilling fluid, and finally, testing physical and chemical parameters of an effective plugging layer formed by the drilling fluid and rock; establishing a three-hole three-permeability model considering a rock matrix field control equation, a rock fracture field control equation and a plugging layer field control equation; and calculating and considering the effective stress around the three-hole three-seepage well of the plugging layer. According to the method, the influence of fluid seepage and solute diffusion rules in the drilling fluid plugging layer on the well circumference stress distribution rule can be effectively analyzed, the formation collapse pressure and fracture pressure can be further calculated in combination with the strength criterion, and the drilling fluid density design is guided.

The invention discloses a disturbance degree unified evaluation method considering soil stress and structural change, and belongs to the technical field of rock soil and underground engineering. The method comprises the following steps: calculating a soil body average effective stress used for representing a soil body stress state, and a body strain and a shear strain used for representing a soil body initial structure; calculating structural parameters for representing the initial structural property of the soil body; and substituting the calculated average effective stress, the shear strain, the body strain and the structural parameters of the soil body into a soil body disturbance degree evaluation formula, respectively calculating soil body disturbance degrees SDD under an unloading working condition and a loading working condition, and evaluating soil body disturbance caused by underground engineering construction. The method has the beneficial effects that the stress level change and the soil structure change caused by underground engineering construction are comprehensively considered, and the accuracy of disturbance degree evaluation is improved; soil disturbance can be accurately predicted before construction, and the method has important guiding significance on actual engineering deformation prediction, reinforcement scheme optimization and the like.

The invention provides a visual characterization method, device and equipment for a deformation rule of a rock microstructure, and relates to the technical field of oil-gas exploration. The method comprises the following steps: acquiring scanning grey-scale map data of an internal structure of a rock under different load conditions; establishing a rock three-dimensional digital core model under different load conditions according to the scanned grey-scale map data and the pre-trained neural network; performing pore structure feature extraction processing according to the rock three-dimensional digital core model to obtain rock pore structure feature parameters, and representing a dynamic deformation rule of the rock micro-pore structure along with effective stress loading according to the rock pore structure feature parameters; performing fracture morphological feature extraction processing according to the rock three-dimensional digital core model to obtain a rock fracture morphological feature parameter system, and representing a rock internal fracture morphological deformation evolution rule according to the rock fracture morphological feature parameter system. According to the method provided by the invention, the real rock micro-pore structure is accurately reflected.

The invention discloses a waste slag storage yard slope stability evaluation and analysis method considering material static liquefaction instability, and the method comprises the steps: obtaining related mechanical parameters of a waste slag storage yard slope with a potential liquefaction region; constructing an elastic-plastic constitutive model, and carrying out iterative calculation on the elastic-plastic constitutive model into which the related mechanical parameters are substituted through an optimization algorithm to obtain optimal simulation parameters; determining a critical state line and an unstable line in a stress space according to the optimal simulation parameters and related mechanical parameters; analyzing the side slope of the waste slag storage yard through a strip division method and an effective stress analysis method to obtain effective stress states of related points on different slip planes; according to the critical state line and the unstable line in the stress space, the effective stress state of each point in the side slope is used for static liquefaction instability possibility judgment, and then the potential liquefaction instability area of the side slope is obtained; and according to the potential liquefaction instability area of the side slope, the waste slag storage yard side slope with the potential liquefaction area is evaluated, so that the safety coefficient of the waste slag storage yard side slope considering the static liquefaction instability characteristic of the material is obtained.

The invention provides a method for testing fracture flow capacity under a shale oil core stress condition. The method comprises the following steps: forming a fracture on a core; carrying out vacuumizing and high-pressure saturated oil treatment on the rock core subjected to fracture forming; according to the core crack type, a plurality of net effective stress points are increased by changing the displacement pressure difference and the confining pressure, and then core outlet end flow data are obtained; a copper foil is utilized to support the crack, different crack opening degrees are simulated, a plurality of net effective stress points are added, flow data of the outlet end of the core are obtained, and shale core flow capacity evaluation under the condition of different crack opening degrees is achieved; after different flowing pressure differences are selected to achieve stable flowing, corresponding flowing data are obtained, and the liquid-phase permeability of the fractured rock core is calculated according to a Darcy formula; and evaluating the flow capacity of the rock core according to result data, comprehensive stress conditions and fracture forms. According to the invention, different fracture forms can be simulated, so that the experimental research is more comprehensive, and a reference is provided for the crude oil flowing capacity of fractured reservoirs in shale oil development at present.

The invention relates to a shale reservoir stratum pore pressure logging prediction method based on an improved Bowers equation, and the method comprises the steps: building an acoustic wave velocity response equation considering the influence of density and organic matter content in combination with the Bowers equation; carrying out a soaking experiment on the rock sample, and obtaining formation acoustic velocity and density subjected to hydration correction based on interval transit time, density and depth resistivity in logging information: obtaining a Bowers equation of a research formation based on the acoustic velocity and density of an undisturbed formation subjected to hydration correction; the Bowers equation of the research stratum is corrected, and an improved Bowers equation of the research stratum is obtained; based on an improved Bowers equation, effective stress and vertical stress of the stratum are calculated; and based on the effective stress and the vertical stress of the stratum, calculating to obtain the stratum pore pressure of the research stratum. According to the corrected Bowers formation pore pressure prediction model established by the invention, the prediction precision is obviously improved, and the development cost is reduced while the occurrence of construction accidents is reduced.

The invention relates to the field of petroleum engineering, and discloses a pore pressure determination method and device, a storage medium and electronic equipment. The method comprises the following steps: determining longitudinal wave time difference and transverse wave time difference of a rock debris sample, respectively performing overburden pressure correction on the longitudinal wave time difference and the transverse wave time difference, and determining a longitudinal wave and transverse wave ratio according to the corrected longitudinal wave time difference and transverse wave time difference; determining the content of each mineral in the rock debris sample and reconstructing the density content and the shale content; according to the density content, the shale content, the longitudinal wave time difference and the transverse wave time difference, the conversion relation between the dynamic and static elastic parameters is determined; determining vertical principal stress according to the density content; determining a relation between a longitudinal-transverse wave ratio and effective stress according to a conversion relation between the dynamic and static elastic parameters and preset static pressure test data; and determining a pore pressure determination model according to the vertical principal stress and the relation between the ratio of the longitudinal wave to the transverse wave and the effective stress. The invention discloses a while-drilling real-time pressure prediction method, and the real-time monitoring effect of the formation pressure is improved.

The invention belongs to the field of seismic liquefaction discrimination of geotechnical engineering, and relates to a three-dimensional site liquefaction discrimination method based on SPT, which comprises the following steps: obtaining site seismic parameters; geological soil layer conditions are obtained; establishing a three-dimensional site grid model; carrying out a field standard penetration test on a soil layer of a typical soil texture type; generating a three-dimensional field actual measurement average standard penetration field; generating a three-dimensional field critical standard penetration field; generating a three-dimensional site anti-liquefaction safety coefficient field; and determining the liquefaction possibility of the three-dimensional site. According to the invention, through two times of correction of the overlying effective stress, the detection cost is reduced while the data reliability is ensured; through a stress coupling correction technology, dynamic coupling analysis of a stress state and a standard penetration value is realized, and the discrimination precision is improved; by establishing a three-dimensional site grid model, spatial distribution characteristics and physical properties of a soil layer and a soil body are represented; and through a three-dimensional visual discrimination system, the liquefaction evaluation of the site can be integrally and visually carried out.

The invention discloses a method for constructing a rock dynamic damage constitutive relation under the freeze-thaw-load effect, and belongs to the technical field of rock damage, and the method comprises the following steps: determining a dynamic damage evolution equation based on evolution characteristics of a rock dynamic damage rate under the freeze-thaw-load effect and a macromechanical parameter change rule; the method comprises the following steps: abstracting a rock under the action of freeze-thaw-load into four parts, namely freeze-thaw damage, load-bearing damage, coupling damage and non-damage, bearing effective stress by the non-damage part, bearing residual stress by the damage part, and establishing a rock constitutive model based on a dynamic damage rate; freeze-thaw cycle and conventional triaxial compression tests of the red sandstone are carried out, and the rationality of the model is verified through test results. According to the method, the model is established in a mode of combining theoretical derivation and test verification, the goodness of fit between the obtained theoretical curve and the test curve is high, the mechanical behavior of rock freeze-thaw load damage can be well reflected, and theoretical guidance can be provided for design and construction of cold region engineering.

The invention discloses a device and a method for testing seepage deformation of a compressive fault fracture zone under the action of reciprocating seepage. Comprising a water supply system, an upstream seepage pressure control system, a downstream seepage pressure control system, a water return system, a seepage pressure chamber, a soil-water separation system, a particle collection system, a confining pressure loading system, a flow monitoring system and a computer servo system, the method comprises the following steps: analyzing the loss particle size distribution and loss amount of fine particles collected by a particle collection system to obtain the relationship among parameters such as permeability coefficient, porosity, particle loss condition, effective stress, time and the like in a fault fracture zone sample seepage deformation process under the conditions of reciprocating seepage and different effective stress; the seepage deformation evolution process of the fault fracture zone sample under the action of reciprocating seepage-different effective stress is explored, and a theoretical basis and technical support are provided for guaranteeing long-term seepage stability of water conservancy and hydropower engineering.

The invention discloses a method for determining the minimum cylindrical shell thickness of a core-filled concrete column, and relates to the technical field of constructions.The method for determining the minimum cylindrical shell thickness comprises the steps that the first cylindrical shell thickness meeting the design bearing capacity condition of the core-filled concrete column is calculated; calculating the thickness of a second cylindrical shell meeting the requirements of the construction pouring stage; calculating a third cylindrical shell thickness meeting the construction requirement that the stirrups and the longitudinal bars are pre-embedded in the cylindrical shell; and selecting the maximum value of the first cylindrical shell thickness, the second cylindrical shell thickness and the third cylindrical shell thickness, and determining the maximum value as the minimum cylindrical shell thickness. According to the method, the minimum column shell thickness value of the core-filled concrete column under different column heights and different design bearing capacities can be quantitatively determined in the design process through an effective acting stress model, a thick-wall cylinder theory and other theoretical models, the core-filled concrete column designed according to the minimum column shell thickness meets the requirements of engineering design, column shell materials can be saved, and the cost is reduced. And the utilization rate of the column shell UHPC material in the core-filled concrete column is improved.

The invention relates to the technical field of oil field drilling engineering, in particular to a while-drilling measurement-based rotary guide system risk identification method and identification terminal, and the method comprises the steps: obtaining while-drilling measurement data; establishing a deep well wall surrounding rock stress-strain model, and constructing a well wall stability discrimination equation; establishing a random nonlinear disturbance force action model, and determining random dynamic response process parameters of the system with the rotary guide drill column under the deep well condition; determining the well wall stability according to the well wall stability discrimination equation, and determining the failure risk of the drill column system with the rotation guide according to the random dynamic response process; according to the method, effective strain and effective stress at the position, r away from a borehole, of a near-well-wall zone are calculated, and a well wall stability judgment equation is obtained through fitting to judge the possibility of well wall instability; and a Newmark method is adopted to carry out time discretization on the stochastic nonlinear dynamic model of the drill string system to invert the stochastic dynamic response process of the stochastic nonlinear dynamic model, and risk factors are clarified.

The invention relates to the technical field of geotechnical engineering, in particular to a sandy soil liquefaction discrimination method which comprises the following steps: collecting geological survey data, seismic parameters and soil test and in-situ test results of a target area, and determining parameters required by numerical simulation; a three-dimensional calculation model is constructed, grids are subdivided, a constitutive model is set, static balance and an initial pore pressure field are established, and the accuracy of the model is verified through mechanical balance and fluid balance; dynamic waves are processed and applied, a free field boundary, a seepage mode and mechanical damping are set, a coupling constitutive model is constructed, and monitoring points are arranged on the liquefiable stratum; determining liquefaction according to the effective stress, the pore water pressure time history curve and the excess pore pressure ratio; according to the invention, vertical and lateral deformation after liquefaction can be predicted, quantitative deformation data can be provided, errors of a standard penetration test are reduced, and the problems of small application range and strong regionality are solved; and the judgment result is more accurate through the verification of the excess pore pressure ratio, and a reliable basis is provided for the design of engineering anti-liquefaction measures.

The application provides a calculation method of pore pressure of a tectonic compression formation. The calculation method of pore pressure of the tectonic compression formation comprises the following steps: S1, obtaining a density trend curve, and performing integral calculation on the density trend curve to obtain overburden pressure S V ; S2, determining total porosity POR of the formation based on acoustic logging, density logging, neutron logging or nuclear magnetic resonance logging; S3, analyzing characteristics of a target layer section to determine a tectonic compression coefficient ACm_C of the formation; S4, solving a pore pressure coefficient PP of a mudstone section based on a pore pressure model corrected based on the tectonic compression coefficient ACm_C; S5, determining a relationship between effective stress P eff and biot coefficient α and total porosity POR; and S6, inversely deducing a pore pressure coefficient of a reservoir section according to the relationship between the effective stress P eff and the total porosity POR. The application solves the problem of low calculation accuracy of the pore pressure calculation method in the prior art.

The invention discloses a shield tunnel electromechanical numerical control and testing integrated model test platform and method, and relates to the technical field of shield construction testing. Comprising the following steps: S1, collecting water-soil machine three-dimensional coupling test data in real time, and performing data preprocessing; s2, reconstructing a pore pressure, water content, stress and average effective stress multi-distribution field; multiple types of residual parameters are calculated, the three-dimensional water-soil coupling balance is evaluated, the hydraulic stress state is judged, and balance control over flow and pressure is executed; s3, when the hydraulic stress state is imbalanced, evaluating and correcting the flux adjusting quantity, and realizing water inlet and outlet flow adjustment; and S4, based on the three-dimensional water-soil coupling balance change rate and the correction flux regulation variable change rate, evaluating dynamic response consistency, updating parameters and correcting a threshold value. The problem that the test precision and the subsequent construction safety are affected due to the fact that an existing shield test device cannot accurately reflect the stress seepage collaborative change rule in the shield construction process under the complex water-rich stratum is solved.

A method includes performing, on a core sample obtained from a reservoir and positioned in a permeability measurement assembly that includes a flow inlet, a permeability operation by flowing a test fluid from the flow inlet and into the core sample and changing an effective stress acting on the core sample. The method also includes determining a natural logarithm of permeability of the core sample as a function of the effective stress, and determining, as a function of the natural logarithm of permeability of the core sample, an initial pore pressure of the reservoir.

The invention relates to the technical field of geotechnical engineering and geological engineering, and discloses a CO2 geological utilization and storage induced earthquake multi-field coupling numerical analysis method, which comprises the following steps of 1, acquiring rock fault geometric characteristic parameters, reservoir geological characteristic parameters, tectonic stress characteristic parameters and construction parameters of a well production point; 2, simulating the CO2 phase change process according to the seepage field, the temperature field, the chemical field and the stress field, constructing a heat-fluid-solid-chemical multi-field coupling mathematical model in the CO2 injection process, including a seepage source confluence item, a thermal field equation, a reaction rate and effective stress, and realizing simulation of the whole fault activation-fracture process under the heat-fluid-solid-chemical multi-field coupling action; the multi-field coupling analysis is more comprehensive; 3, injection-induced fault activation simulation is carried out, and normal stress and shear stress of the fault surface and the fault slip rate are analyzed; and step 4, non-seismic slippage and seismic slippage are evaluated, corresponding seismic moments and induced seismic magnitudes are output, and the seismic nucleation precision is high.