25 results about "Shrinkage strain" patented technology

The invention relates to the technical field of online monitoring, in particular to a concrete formwork stress monitoring method and system based on an intelligent sensor, and the method specifically comprises the steps: collecting environment data of a concrete pouring site, building a concrete environment coupling dynamic model, and outputting a formwork side pressure correction value; collecting working condition data of the template, and importing the working condition data of the template into the random vibration response coupling model to generate a space-time stress threat cloud picture borne by the template in real time; a hydration heat temperature field in the concrete pouring process is monitored in real time, and chemical shrinkage strain generated in the concrete pouring process is obtained; and obtaining a template comprehensive failure index according to the stress threat and the chemical shrinkage strain in the space-time stress threat cloud picture, calculating a time-varying failure probability, and triggering graded early warning through the template comprehensive failure index and the time-varying failure probability. According to the invention, the problem of lagging or misjudgment of failure early warning of the template in the prior art is solved.

The invention provides a curing process online monitoring method for a variable-thickness composite material component, and relates to the technical field of structural health monitoring of composite materials, and the method comprises the steps: collecting original monitoring data of each optical fiber sensing point in the variable-thickness composite material component; based on a preset temperature sensitivity coefficient and a preset strain sensitivity coefficient, performing temperature-strain double-parameter decoupling on the original monitoring data to obtain chemical shrinkage strain; according to the chemical shrinkage strain and the change rate, a gel point, a maximum heat release rate point and a glass transition interval in the resin curing process are obtained, and curing state characteristics are constructed; and determining a curing stage corresponding to the variable-thickness composite material component based on the curing state characteristics, calculating a curing degree gradient, and when the curing degree gradient is greater than or equal to a preset process safety threshold value, sending a closed-loop regulation and control instruction to curing equipment so as to adjust the curing process of the variable-thickness composite material component, according to the invention, the curing monitoring precision and stability can be improved.

The application discloses a kind of bridge structure in concrete shrinkage and creep calculation method, equipment and storage medium, the method includes using initial strain method to calculate stress increment and creep strain increment in different period, and then calculate stress and creep strain at different time;According to the stress increment of different period, stress-strain relationship and creep coefficient fitting function calculation period Δt n+1 Internal concrete creep caused by unit equivalent node load increment;According to concrete shrinkage strain increment calculation period Δt n+1 Internal concrete shrinkage caused by unit equivalent node load increment.The application can accurately calculate the shrinkage and creep effect of concrete in the structure when applied to bridge structure analysis, greatly improves the calculation efficiency and saves storage space.

This will suppress cracking and reduce costs. [Solution] A floor structure having a lower floor slab and an upper floor slab provided on the lower floor slab, wherein the lower floor slab is made of unreinforced concrete or reinforced concrete using first concrete, and the upper floor slab is made of reinforced concrete using second concrete, and the shrinkage strain of the second concrete is smaller than the shrinkage strain of the first concrete.

This invention discloses a method for predicting the leakage of water from the sealing plug of a water-sealed cavern, relating to the field of seepage control technology in underground water-sealed cavern engineering. The method includes: calculating the spatiotemporal temperature distribution and effective cooling difference during the hydration heat process and subsequent cooling process of the concrete sealing plug; introducing a stress relaxation coefficient to calculate net shrinkage strain, thereby obtaining real-time tensile stress and tensile strength; comparing the two, determining the occurrence of opening cracks when the tensile stress exceeds the tensile strength, and calculating the equivalent crack width; establishing a seepage prediction calculation model based on the cubic law of fluid mechanics and obtaining the seepage volume; finally, converting the seepage volume into a capacitance value to establish a time curve, and comparing it with acceptance standards. This invention upgrades empirical seepage control measures into a quantifiable and predictable guidance system, providing a scientific basis for temperature control and precise timing of grouting during sealing plug construction.

The utility model relates to the technical field of bridge deck slab reinforcement and repair, and discloses a low-shrinkage ultra-high performance concrete pavement reinforced bridge deck structure which comprises a bridge deck slab, a reinforcement layer and anchoring parts. The reinforcing layer at least covers the upper surface and is formed by pouring ultra-high performance concrete with shrinkage strain smaller than 150 mu epsilon when the ultra-high performance concrete reaches a stable state, and the anchoring part is embedded between the bridge deck slab and the reinforcing layer. According to the utility model, the concave-convex textures enhance the interface friction force between the reinforcing layer and the bridge deck slab, so that the integrity of the bridge deck structure is stronger; the reinforcing layer poured by the low-shrinkage ultra-high performance concrete has better bearing capacity, rigidity and ductility; the connection firmness of the reinforcing layer and the bridge deck slab is improved through the anchoring parts; by means of the improvement, the bridge deck structure is not prone to interface void phenomena, cracks, voids, pitted surfaces and the like, the overall mechanical property of the bridge deck structure is effectively improved, and the service life of the bridge deck structure is effectively prolonged.

The invention relates to the technical field of concrete, and particularly discloses solid waste lightweight aggregate low-shrinkage ultra-high performance concrete and a preparation method thereof. The solid waste light aggregate low-shrinkage ultra-high performance concrete is prepared from the following raw materials in parts by weight: 300 to 400 parts of solid waste mixed light aggregate, 900 to 1000 parts of light cement-based cementing material, 65 to 75 parts of composite micro-expansion agent, 200 to 350 parts of high-flow-state fine aggregate, 25 to 35 parts of water reducing agent, 0.1 to 3 parts of retarder, 15 to 156 parts of anti-cracking fiber, 200 to 250 parts of water, 3 to 6 parts of shrinkage reducing agent and 1 to 5 parts of defoaming agent. The solid waste lightweight aggregate low-shrinkage ultra-high performance concrete provided by the invention has the advantages of high compressive strength, low shrinkage strain, low volume weight, good working performance and good crack resistance.

The invention relates to the technical field of underground tunnel engineering construction, in particular to a construction method and device for resisting shrinkage cracking of tunnel wall concrete. The construction method comprises the steps that S1, before wall concrete is poured, prestressed tendons are evenly distributed in a wall; s2, the prestressed tendons are subjected to graded tensioning for m times, m is larger than or equal to 2, the tensioning force of each time of tensioning is 0.15 sigmacon < = 0.5 sigmacon, and sigmacon is tensioning control stress; and S3, wall concrete pouring and curing are conducted, the concrete strength and the shrinkage strain value are monitored during curing, when the concrete strength reaches 30% or above of the design strength and the shrinkage strain value is larger than or equal to 50 mu epsilon, the prestressed tendons are released in a grading mode, and the releasing stress of each grade is smaller than or equal to 0.5 sigmacon. According to the method, cooperative control of graded tensioning and graded releasing is carried out in the wall concrete, so that the concrete keeps reasonable pre-compressive stress in each hardening stage, the tensile stress generated by shrinkage is counteracted, cracks of the wall are avoided, and the structural integrity of the tunnel wall is guaranteed.

The invention relates to the technical field of material forming, in particular to a preparation method of a high-strength and high-shrinkage-strain-ratio alpha and near-alpha type titanium alloy pipe. The method comprises the following steps: 1) carrying out Pilger two-roller cogging rolling on a titanium alloy pipe blank to obtain a cogging rolled pipe; (2) after cogging rolling, recrystallization annealing is conducted, and an annealed pipe is obtained; (3) three-roller intermediate rolling is conducted on the titanium alloy pipe subjected to cogging annealing, and an intermediate rolled pipe is obtained; 4) performing vacuum stress relief annealing after intermediate rolling to obtain an intermediate annealed pipe; 5) performing Pilger two-roller finished product rolling on the intermediate annealed pipe to obtain a finished rolled pipe; according to the method, the shrinkage strain ratio of the pipe is remarkably increased, and the technical index requirements for high strength and the high shrinkage strain ratio of the pipe are met. The method comprises the following steps of (1) rolling the pipe into a finished product, (2) carrying out vacuum stress relief annealing on the finished product rolled pipe to obtain a finished product annealed pipe, (3) carrying out finished product straightening on the finished product annealed pipe and (4) carrying out finished product acid pickling on the straightened finished product annealed pipe to obtain the titanium alloy pipe.

The invention relates to the technical field of civil engineering, in particular to a concrete structure random shrinkage creep calculation method which comprises the following steps: acquiring data of a concrete structure needing to be calculated; calculating a creep coefficient and shrinkage strain curve of the concrete structure; a concrete shrinkage and creep calculation model is constructed, and an updated stress-strain relation is obtained; combining a concrete shrinkage creep test database to construct a concrete shrinkage creep randomness coefficient, and finally obtaining a shrinkage creep deformation calculation result priori interval of the concrete structure; establishing a Gaussian process regression model; and performing Bayesian inference by adopting a Monte Carlo-Markov chain method and a Gaussian process regression model to obtain a posterior interval of a concrete structure shrinkage creep calculation result needing to be calculated. The problems that an existing concrete structure is high in shrinkage creep randomness and insufficient in prediction precision are solved. According to the method, Gaussian process regression is adopted, and the problem that a large amount of calculation cost of finite element calculation is needed in Bayesian inference is solved.

The invention discloses a concrete shrinkage stress calculation method and system based on a humidity diffusion coefficient, and relates to the technical field of concrete mechanics, and the method comprises the steps: carrying out the error inversion of space humidity distribution data and multi-point actual measurement humidity data, constructing a humidity diffusion coefficient multi-point fitting problem, carrying out the multi-point fitting solving through employing a least square method, and calculating the shrinkage stress of concrete. Outputting a local humidity diffusion coefficient; inputting the local humidity diffusion coefficient and the spatial humidity distribution data into a hybrid intelligent model, performing humidity-induced shrinkage strain prediction, and outputting a shrinkage strain time sequence result; combining a shrinkage strain time sequence result with a material aging parameter, calculating an equivalent shrinkage stress tensor field of each space node, and constructing a stress migration path map; and calculating the conductivity and path dependence of each time-space node in the stress migration path map, and generating a shrinkage stress evolution path map. According to the method, the scientificity and reliability of structural performance evaluation are enhanced, and the safety and durability management level of the concrete structure are improved.

The application discloses a kind of super-low temperature rock mechanics response monitoring method, system and equipment, and the super-low temperature rock mechanics response monitoring method includes: the rock sample with strain-temperature sensitive grating array and temperature reference grating array being mutually connected in series is placed in super-low temperature environment loading system;Start super-low temperature environment loading system, and the wavelength shift of each grating and the wavelength shift of each grating are measured in real time;The wavelength shift of one of temperature reference grating measured in temperature reference grating array is used to calculate the real temperature of rock sample corresponding grating measuring point;The physical model of strain-temperature sensitive grating center wavelength shift in strain-temperature sensitive grating array is established, and the total strain of rock sample grating measuring point is calculated according to real temperature and the physical model;According to the total strain of rock sample and the natural freeze shrinkage strain of rock sample, the mechanical strain generated by the ice expansion of pore water of rock sample is calculated, and frost heaving stress.

This utility model discloses a laser-sensor-based concrete self-shrinkage deformation detection device, belonging to the field of building material performance testing technology. The device includes a base plate. Through the arrangement of the detection components and corrugated pipe, the corrugated pipe linearly converts the concrete shrinkage strain into axial displacement during use, while guide rollers constrain radial displacement. The laser optical path and the fiber optic sensor sensing path are physically isolated, allowing the two systems to operate independently. Furthermore, a laser displacement sensor replaces the infrared sensor, utilizing the strong monochromaticity and good directionality of laser light, along with a laser reflector, to eliminate the influence of environmental temperature and humidity changes on the optical path and improve resolution. Distributed fiber optic sensors are pre-embedded within the corrugated pipe wall, fusing with laser displacement data to construct a "global displacement-local strain" dual feedback mechanism. This multi-sensor collaborative design significantly improves system reliability.

The application discloses a kind of high durability crack resistance type water stable composite material and its preparation method and application, belong to road engineering and building material technical field.The high durability crack resistance type water stable composite material provided in the application includes aggregate, composite cementitious material, internal curing agent, toughening fiber, shrinkage-reducing toughening agent and water.The composite cementitious material is prepared from Portland cement, S95 grade slag powder, modified steel slag powder;The internal curing agent is porous ultra-fine mineral particles pre-adsorbed with liquid curing agent;The toughening fiber includes at least two of polyester fiber, polyvinyl alcohol fiber, polypropylene fiber;The shrinkage-reducing toughening agent includes polyether shrinkage-reducing agent-nanosilica composite.The material of the application realizes the unity of high later strength, low drying shrinkage strain, high toughness and excellent frost resistance through multi-component synergy, especially suitable for high durability and crack resistance requirement high road base and building cushion engineering, with environmental protection and economic benefit.

The present application provides a kind of cast-in-place fair-faced concrete wind tunnel body crack resistance construction method, belong to wind tunnel technical field, the present application is by preparing low heat high crack resistance concrete and incorporating basalt fiber and double expansion source expansion agent, pre-embedded cooling water pipe network and temperature monitoring point in tunnel body, according to hydration heat temperature rise control equation dynamic adjustment cooling water flow, using formwork pre-deformation compensation design eliminates forming error, according to the way of layered pouring control temperature rise rate, implement early curing and through shrinkage strain game model optimization curing parameter, after stripping, carry out precision measurement and feedback correction formwork deformation prediction equation, solve the technical problem that cast-in-place fair-faced concrete wind tunnel body is caused by hydration heat temperature rise and produces early crack due to internal and external temperature difference too large.

The invention relates to the technical field of building material testing, and discloses a 3D printing cement-based material plastic shrinkage testing method which comprises the following steps: filling a detachable mold with a to-be-tested cement-based material, and compacting the to-be-tested cement-based material; removing a side template of the detachable mold within 1-2 hours after the initial setting of the material; placing the sample in a dry hot air environment, and enabling the sample to generate a crack at the stress constraint device; observing and measuring the width of a crack generated at the stress constraint device; and calculating the plastic shrinkage strain according to the ratio of the sum of the crack widths of the plurality of observation points to the length of the sample. According to the invention, accurate quantification of the plastic shrinkage strain is realized through the detachable three-surface exposed mold, the stress constraint device induces the crack, and the crack width is measured at multiple observation points.

The application provides a concrete shrinkage and cracking prediction method based on multi-dimensional sensing data coupling, relates to the technical field of concrete shrinkage and cracking prediction methods, and comprises the following steps: a multi-parameter weighted degradation evaluation method is used to calculate the degradation parameters of concrete; a temperature and humidity coupling parameter of concrete is constructed; the autogenous shrinkage strain, the drying shrinkage strain and the temperature shrinkage value of the concrete in a monitoring period are weighted and calculated to obtain the theoretical shrinkage strain value of the concrete in the monitoring period; based on the corrected theoretical shrinkage strain value and the full-cycle crack coefficient, a threshold response method is used to construct a comprehensive risk index, and the comprehensive risk index is classified and early warned. Through time-varying normalization and nonlinear correction, the dynamic interaction between the hydration process and the environmental influence is quantified by synchronously integrating the resistivity, the porosity, the temperature difference and the external environmental data.

The application provides a kind of underground interchange main body side wall structure concrete crack resistance waterproof construction method, it is related to underground engineering concrete construction technical field, the application is by dividing side wall into multiple sub-regions, obtains the geometric curvature of each sub-region, structural constraint, cross section variation, temperature action, shrinkage strain, load tensile stress, joint adjacent and waterproof weak parameter;Based on the first six parameters, calculate the crack resistance risk value, combined with the last two parameters to calculate the waterproof failure risk value, and determine the comprehensive protection requirement value accordingly;According to the comprehensive protection requirement value, the sub-regions are classified, and the target areas that need to be strengthened are identified;Different regions are respectively used C40 concrete with conventional or hybrid fiber optimal ratio, and the pouring segment length is dynamically determined according to the maximum crack resistance risk value, to realize differentiated crack resistance waterproof construction.

The present application belongs to the field of concrete risk analysis, and discloses a cast-in-place concrete anti-cracking and waterproof integrated intelligent evaluation system based on machine learning; comprising: acquiring temperature sequences, strain sequences, surface thermal image sequences and water seepage sensitive area image sequences of different monitoring partitions; extracting internal and external temperature difference growth, cooling duration, shrinkage strain growth, strain gradient enhancement, crack width growth, crack extension, wet trace expansion and thermal anomaly migration fragments; obtaining anti-cracking risk characterization results by analyzing the relevance of the change attributes in the internal and external temperature difference growth fragments and the change attributes in the shrinkage strain growth fragments; obtaining waterproof risk characterization results by analyzing the relevance of the expansion change attributes in the crack extension fragments and the diffusion change attributes in the wet trace expansion fragments; performing integrated evaluation to obtain anti-cracking and waterproof comprehensive evaluation results. The present application realizes anti-cracking and waterproof risk linkage evaluation and enhances risk identification capability.

The invention provides a concrete shrinkage cracking prediction method based on multi-dimensional perception data coupling, and relates to the technical field of concrete shrinkage cracking prediction methods, and the method comprises the steps: employing a multi-parameter weighted degradation evaluation method to calculate concrete degradation parameters; constructing temperature and humidity coupling parameters of the concrete, and performing weighted calculation on the authigenic shrinkage strain, the drying shrinkage strain and the temperature shrinkage value of the concrete in the monitoring period to obtain a theoretical shrinkage strain value of the concrete in the monitoring period; and on the basis of the corrected theoretical shrinkage strain value and the complete-period crack coefficient, constructing a comprehensive risk index by adopting a threshold response method, and carrying out classified early warning on the comprehensive risk index. The resistivity, the porosity, the temperature difference and the external environment data are synchronously integrated, and the dynamic interaction between the hydration process and the environment influence is quantified through a time-varying normalization method and a nonlinear correction method.

The application belongs to the technical field of ocean engineering, and discloses a construction method of a fiber-reinforced high-performance seawater-sea sand concrete shrinkage prediction model, which comprises the following steps: S1, introducing a seawater concentration correction term into a limit shrinkage strain of an existing concrete shrinkage prediction model, and calculating a seawater concentration influence coefficient; S2, introducing an effective humidity correction term into a humidity function of the existing concrete shrinkage prediction model, and calculating a humidity perception coefficient; S3, constructing a fiber constraint function and introducing a fiber inhibition coefficient; S4, outputting the fiber-reinforced high-performance seawater-sea sand concrete shrinkage prediction model by using a time development function in combination with the seawater concentration correction term, the effective humidity correction term and the fiber inhibition coefficient. The shrinkage prediction model established by the application adopts a theoretical framework of multi-factor coupling, completely considers the interactive influence of seawater chemical effects, microphysical mechanisms and fiber mechanical constraints, and can accurately represent the shrinkage law of high-performance seawater-sea sand fiber concrete.

The invention discloses a concrete early-age self-constriction testing method considering an interface transition area. The method comprises the following steps: solving self-constriction elastic strain of cement paste; obtaining early-age self-constriction creep strain and total self-constriction strain of the cement paste in combination with a time evolution rule of pore pressure caused by hydration reaction; calculating the capillary pressure of the cement paste, the saturation of the cement paste and the bulk modulus of the cement paste; solving the effective elastic modulus of the effective inclusion phase in the concrete system; putting the equivalent inclusion phase into the cement paste to obtain the elastic modulus, Poisson's ratio and bulk modulus of the concrete; the intrinsic strain of the self-constriction of the cement paste is transmitted to the overall dimension of the concrete through a microcosmic homogenization method, and the self-constriction strain of the concrete is obtained. According to the concrete self-shrinkage testing method, the characteristics of an interface transition area are considered, the real early-age deformation behavior is accurately reflected, and the concrete self-shrinkage testing method has engineering applicability and provides a reliable basis for anti-cracking design and durability improvement of high-performance concrete.

According to the intelligent maintenance system and method for the U-shaped stack box rigid frame aqueduct, the intelligent maintenance system integrates a temperature monitoring module, an environment monitoring unit, an evaporation monitoring module, a strain monitoring unit, a solar maintenance water module, a spraying execution module and an intelligent control system; and a set of intelligent maintenance system for the U-shaped stack box rigid frame aqueduct based on multi-source data fusion is constructed. Through temperature, evaporation and strain multi-source data fusion, real-time monitoring of concrete internal and external temperature difference, surface water loss and key part shrinkage strain is realized, and perception precision and comprehensive perception of concrete are improved. Differential spraying strategies are implemented for different areas such as thick bottom plates, thin walls and haunch angles, the temperature gradient and drying shrinkage are effectively controlled, early cracks are prevented, and accurate regulation and control of concrete are achieved; a strain change rate is introduced as a control parameter, and when strain development is too fast, a maintenance scheme is automatically adjusted, so that active intervention of a cracking risk is realized; the maintenance water is heated by solar energy, and partitioned spraying is combined, so that energy consumption and water consumption are remarkably reduced, and energy conservation and environmental protection are achieved; the system has closed-loop control, real-time alarm and environment self-adaption capabilities, ensures that the maintenance process is stable and controllable, and improves the durability of the structure.

This invention discloses a low-alkalinity, high-strength filling material, its preparation method, and its application, belonging to the technical field of mine filling materials and solid waste resource utilization. The filling material comprises cementitious materials, aggregates, and water, with a cementitious material to aggregate mass ratio of 1:4 to 1:8, and a slurry solid phase mass concentration of 65-72%. The cementitious material includes slag, fly ash, phosphogypsum, acetic acid, phosphate, and an alkalinity regulator. Acetic acid is used as the main activator to accelerate hydration and inhibit shrinkage, while phosphate assists in solidification to reduce Ca2+. 2+ The material is permanently cured into insoluble calcium phosphate, achieving multi-element synergistic activation. The material exhibits a 28-day compressive strength ≥2.5 MPa, a leachate pH ≤9, and maintains a stable pH below 9 even after 180 days of long-term immersion. The 60-day drying shrinkage strain is 385–450 × 10⁻⁶. ‑6 It has a high solid waste utilization rate, simple process, and no special maintenance required, effectively solving the technical problems of high alkalinity and long-term alkali return of traditional filling materials.

The invention discloses an ultralow-temperature rock mechanical response monitoring method, system and equipment. The ultralow-temperature rock mechanical response monitoring method comprises the following steps: putting a rock sample into an ultralow-temperature environment loading system, wherein a strain-temperature sensitive grating array and a temperature reference grating array which are connected in series are implanted into the rock sample; starting an ultralow-temperature environment loading system, and measuring the wavelength drift distance of each grating and the wavelength drift distance of each grating in real time; the real temperature of the corresponding grating measuring point of the rock sample is calculated by using the wavelength drift distance of one temperature reference grating measured in the temperature reference grating array; establishing a physical model of central wavelength drift of the strain-temperature sensitive grating in the strain-temperature sensitive grating array, and calculating the total strain at the grating measuring point of the rock sample according to the real temperature and the physical model; and according to the total strain of the rock sample and the natural freezing shrinkage strain of the rock sample, calculating the mechanical strain generated by pore water freezing expansion and the frost heaving stress of the rock sample.