15 results about "Strength reduction" patented technology

The invention discloses a landslide construction simulation method based on finite elements, particularly relates to the field of construction simulation, and realizes whole-process dynamic simulation through GTS-NX software. Firstly, a three-dimensional finite element model is established based on geological exploration data, a Mohr-Coulomb elastic-plastic constitutive model is adopted, and the bulk modulus and the shear modulus are calculated through the elastic modulus and the Poisson's ratio. The initial ground stress is simulated by adopting a self-weight stress field method, and the initial displacement influence is eliminated by adopting a displacement difference method. In construction process simulation, the unit passivation / activation technology is adopted to accurately reproduce the excavation and support time sequence, and cyclic calculation of excavation-stress release-support-balance is achieved. In nonlinear analysis, superposition of an elastic stress field and a plastic stress field is considered, and an unloading influence factor is introduced to correct anisotropy of a deformation modulus. A safety coefficient is calculated through a strength reduction method, a multi-working-condition evaluation system is established, a monitoring data fusion and parameter inversion mechanism is developed, and a three-level early warning system is formed.

The invention relates to a rock-soil-building block collaborative slope reliability analysis method considering spatial variability. The method comprises the following steps: establishing a slope finite element model; aiming at the finite element model, constructing an autocorrelation random field which takes a soil mass parameter as a variable and has a discrete characteristic by using a Cholesky Decomposition midpoint method; coupling the self-correlation random field based on a Copula model to form a cross-correlation standard uniform random field, and performing equal probability conversion on the cross-correlation standard uniform random field to form a cross-correlation random field in logarithmic normal distribution; and inputting the generated random field into a finite element model, obtaining a safety coefficient by using a strength reduction method, and determining the slope reliability based on a Monte Carlo method. According to the method, the finite element analysis result is closer to the actual situation, and the accuracy of the reliability analysis result is remarkably improved.

The invention belongs to the field of structural engineering, and particularly relates to a concrete compressive strength calculation method considering a strain rate effect and a size effect. The concrete compressive strength formula considering the size effect and the strain rate effect at the same time is deduced from the size effect formula and the strain rate effect formula of the concrete compressive strength. The formula comprises a constant term, a strain rate effect term, a size effect term and an interaction term. The constant item reflects the static strength of the concrete cubic test piece, the strain rate effect item reflects the strength improvement caused by strain rate increase, the size effect item reflects the strength reduction effect caused by test piece size increase, and the interaction item reflects the strain rate effect increase caused by the size increase and the size effect reduction caused by the strain rate increase. And finally, fitting all test data by adopting a multiple regression method to obtain various parameters of the concrete compressive strength. The formula fitting effect is good, the regression residual error is small, and the adaptability of the calculation method is verified.

This invention discloses a multi-field coupled analysis method for loess slopes considering the influence of porosity, comprising: geometric modeling using finite element software; establishing a constitutive model related to porosity; introducing a porosity random field and atmospheric boundary conditions; calculating the slope safety factor using an improved strength reduction method; and obtaining the safety factor. The advantage of this invention is that the improved strength reduction method can be better used for calculating the slope safety factor and better simulates the stability of loess slopes under hydraulic coupling conditions.

The application discloses a kind of based on deformation monitoring data's slope instability evaluation method, it is related to slope engineering monitoring data analysis field, method is: obtaining the related data such as topography, stratum, foundation monitoring point in the range around slope;According to the distribution of deformation foundation monitoring point and deformation fitting potential sliding surface;Establish three-dimensional finite element model of slope, and determine the cohesion and internal friction angle of potential sliding surface by inversion;The inversion cohesion and internal friction angle of sliding surface are calculated by strength reduction method, and the safety factor of slope is determined;According to the horizontal displacement direction of foundation monitoring point and potential unstable slope body, the sliding direction of slope is determined;Finally, the slope, potential unstable slope body and its sliding direction are displayed through visual platform, and the volume of potential unstable slope body and the safety factor of slope are displayed by text.The application determines the three-dimensional sliding surface of slope by surface fitting, and then calculates the safety factor of slope by parameter inversion and strength reduction method, realizes the early warning description of slope instability form including instability volume, direction and other characteristics.

The embodiment of the invention provides a safety evaluation method and system for a double-angle steel roof truss and a storage medium, and the safety evaluation method comprises the steps: comparing a comprehensive corrosion damage parameter and a corrosion rate limit value of a to-be-evaluated steel member, and when the comprehensive corrosion damage parameter is smaller than the corrosion rate limit value, judging whether the to-be-evaluated steel member is the corrosion rate limit value; if yes, calculating the equivalent tensile bearing capacity after corrosion according to the steel strength reduction coefficient and the comprehensive corrosion damage parameter; the actual internal force borne by the steel member to be evaluated is calculated, and the resistance response-effect ratio is obtained based on the actual internal force and the equivalent tensile bearing capacity after corrosion; and obtaining a safety evaluation result based on the resistance response-effect ratio. According to the safety evaluation method provided by the invention, the safety grade of each steel member of the double-angle steel roof truss can be conveniently and accurately judged, data support is provided for whether the steel roof truss needs to be reinforced or replaced subsequently or not, and the reliability and economical efficiency of operation and maintenance of an industrial factory building are improved.

The invention belongs to the field of surrounding rock pre-reinforcement, and relates to a surrounding rock pre-reinforcement method and system.The surrounding rock pre-reinforcement method comprises the steps that the real-time tunnel face surrounding rock grade and rock mass parameters are obtained, and the rock mass parameters comprise the elastic modulus, the cohesive force and the internal friction angle; constructing numerical models under different grades of surrounding rocks based on the real-time tunnel face surrounding rock grades and rock mass parameters; based on the numerical models under different grades of surrounding rocks, a strength reduction method is adopted, and the safety coefficient of the tunnel face is calculated through a finite difference model and a cuspidal point mutation model to obtain a surrounding rock pre-reinforcement strategy; and the surrounding rock is pre-reinforced in real time according to the surrounding rock pre-reinforcing strategy. The problems of poor safety and low efficiency of tunnel construction caused by an immobilized surrounding rock pre-reinforcement strategy aiming at a complex and changeable geological environment are solved.

The invention relates to a reliability analysis method suitable for sliding failure of a deep foundation pit, and belongs to the technical field of reliability analysis of geotechnical engineering. The invention discloses a reliability analysis method suitable for sliding failure of a deep foundation pit. The method comprises the following steps: collecting landform and soil physical and mechanical parameters of an excavation site of the deep foundation pit; establishing a finite element model according to the construction design drawing and the physical and mechanical parameters of the soil body; monitoring equipment is installed to monitor the working state of the foundation pit in real time, the result is compared with a finite element model result, and parameters of the finite element model are updated in real time; units in the finite element model are extracted, and a random field model is established according to the distribution condition of soil material parameters; calculating a safety coefficient under each random field model according to a strength reduction method; and converting the safety coefficient into a functional function, calculating the first four moments of the functional function by adopting a high-order moment method, and solving the failure probability and reliability of the foundation pit slippage. The risk of foundation pit slippage failure is evaluated, and the risk of foundation pit slippage is predicted and monitored in real time.

The invention provides a surface mine slope reinforcement and protection method and system, and relates to the technical field of data processing, and the method comprises the steps: obtaining geological parameters of a surface mine slope; constructing a finite element model of the surface mine slope according to the geological parameters of the surface mine slope; determining the safety coefficient of the surface mine slope through a finite element strength reduction method; judging whether the safety coefficient is greater than a safety threshold; if yes, determining that the surface mine slope is in a stable state without reinforcement; otherwise, determining that the surface mine slope is in a dangerous state and needs to be reinforced, and entering the next step; generating a plurality of reinforcement protection schemes; loading a reinforcement protection scheme into the finite element model of the surface mine slope; determining the safety coefficient and the potential sliding surface of the surface mine slope after the reinforcement protection scheme is loaded; and performing multi-objective optimization to determine an optimal reinforcement protection scheme by taking the improvement of the safety coefficient, the reduction of the potential sliding surface area and the reduction of the reinforcement cost as objectives.

The present invention discloses a method for analyzing the stability of soil slopes based on the precise finite element method, which includes establishing a two-dimensional slope model and dividing the grid; using the modified hyperbolic circularized Mohr-Coulomb yield constitutive model to determine whether the soil mass yields. If yielding occurs, an accurate explicit Euler algorithm will be used for stress redistribution, and the stress point will always be ensured to be on or within the yield surface through stress back-pulling; for the solution of the non-linear equations, Newton-Raphson iteration is used for solution; the strength reduction method is introduced, and a failure criterion with sufficient accuracy requirements is adopted. The safety factor of the slope is obtained through iterative search, and data such as the displacement and plastic zone of the slope can also be obtained through post-processing of the results. The present invention is reasonable and accurate for the stability analysis of slopes, can give a high-precision slope safety factor, and at the same time, based on the data such as the slope displacement and plastic zone calculated, it can provide a reasonable basis or suggestion for the implementation of slope engineering prevention and control measures.

The application discloses a kind of multi-line parallel pipeline jacking reasonable construction sequence design methods, using numerical calculation means, respectively calculate the stability safety factor K of different pipeline cover layer thickness H, different interlayer width D etc. ij Between different pipeline jacking sequence of the i-th working condition, compare the stability safety factor K of pipeline cavern ij Size, sequentially select the minimum value K ijmin Of each pipeline safety factor under the i-th working condition, compare the K ijmin Value size under different working conditions and select the maximum max [K ijmin ], the pipeline construction cavern max [K ijmin ] corresponding working condition under the pipeline construction jacking sequence of multi-line parallel pipeline is optimal jacking sequence.The application uses finite element strength reduction method to obtain the stability safety factor K of pipeline cavern, compares the stability safety factor K of cavern under different jacking sequence of working condition, and the pipeline construction jacking sequence with maximum safety factor is taken as the reasonable jacking sequence of pipeline construction under the working condition.

The application discloses a method for determining a filled wall constitutive model considering stiffness contribution, and relates to the field of finite element simulation, which comprises the following steps: establishing a five-section constitutive model of a diagonal bracing, determining the elastic modulus of the diagonal bracing, the tangent modulus of a strengthening section of the diagonal bracing, the corresponding secant modulus of the ultimate strain of the diagonal bracing, the ultimate strength of the diagonal bracing, the yield strength, the residual strength, the starting point strain corresponding to the ultimate strength of the diagonal bracing, and the end point strain corresponding to the ultimate strength of the diagonal bracing, correcting the ultimate strength of the diagonal bracing, the yield strength and the residual strength by using a strength reduction coefficient, and correcting the starting point strain corresponding to the ultimate strength of the diagonal bracing by using a starting point strain correction coefficient. The application can give material parameters of a simplified model corresponding to a wall body under the influence of different factors, and then accurately simulate the stiffness contribution of different wall bodies at different stages to the structure, so as to realize a structure modeling method considering the stiffness of the filled wall.

A method for analyzing the overtopping failure of earth-rock dams based on the material point method belongs to the field of numerical simulation technology in civil engineering and hydraulics. The steps are as follows: S1, read in the material point information for each zone, background mesh information, material constitutive models and parameters of the material points, load information of the material points, and related calculation parameters; S2, based on the material point adaptive mapping technique, update the position and momentum of the material points in each time step; S3, calculate the equivalent plastic strain of the material points, consider the fluid-solid transformation of the material points in the dam area through the strength reduction method, and update the stress of the material points according to the constitutive models of the material points in each zone; S4, repeat S2 and S3 until all time steps are completed, and output the deformation and reservoir water level changes at typical moments during the overtopping failure process of the earth-rock dam. This invention uses adaptive mapping to improve the computational efficiency of large-scale problems, effectively reflects the scouring effect of reservoir water on the dam slope during the overtopping process, and reasonably reproduces the evolution process of the overtopping failure of earth-rock dams.

The invention provides a slope support scheme evaluation method and system, and is suitable for the technical field of slope support. The method comprises the steps of index determination, index weight calculation, index scoring and comprehensive score calculation, and a comprehensive slope support scheme evaluation system is constructed by combining multi-dimensional indexes. Geotechnical parameters are dynamically adjusted by adopting a strength reduction method, a relation between slope crest displacement and a safety coefficient is fitted through an objective function, an optimization algorithm is started to accelerate convergence after a polynomial curve is generated by introducing pre-iteration, and the problems that time is consumed when multiple schemes are compared and selected, and safety coefficient calculation consumes much time are solved. A construction difficulty index and a surrounding environment-friendly degree index are quantified, and related parameters are input through a system for automatic scoring.

The application discloses a kind of deep stage cemented filling body strength calculation method considering mining and filling timing, comprising the following steps: S1, construct the three-dimensional finite element model of underground ore body mining and filling mining and filling timing process, numerical simulation calculation is carried out;S2, the displacement cusp mutation analysis function of typical measuring point is established by strength reduction method to determine the threshold value of total displacement and safety factor, and the rationality of threshold value is verified by the displacement nephogram and stress nephogram of finite element cemented filling body numerical model, qualitative analysis;S3, by column network discrete method, the three-dimensional analysis model of cemented filling body strength requirement is reconstructed, and the volume of cemented filling body fracture surface and failure area is determined according to the threshold value of total displacement and safety factor, and finally the strength required by cemented filling body is determined.The strength of filling body determined by the method is accurate and reasonable, effectively solves the problem of filling mining safety and economic balance, and is especially suitable for the strength requirement calculation of cemented filling body of deep stage open stope subsequent filling mining method.