For underground powerhouse in high geostress area, the excavation of the lower powerhouse cavern after the completion of the pouring of the rock-anchored crane beam may have an adverse impact on the crane beam. Aiming at this problem, three-dimensional elastoplastic finite element method was used to analyze the stress and deformation, the stress of the anchor and the stability of the crane beam of an underground powerhouse during construction and operation period. The results show that in the high geostress field, the rock-anchored crane beam will have large deformation, and the joint surface between the beam and the surrounding rock will have large tensile stress. After the crane beam is poured, the stress and deformation of the beam will increase greatly in three stages. As the excavated part is far away from the beam, the stress and deformation of the beam will become gentle, and the safety factor of the joint surface between the beam and the wall will be large, which can provide a reference for the crane beam pouring and cavern construction in similar projects.

Columns are commonly used in water conservancy project to support the upper structure. In order to ensure the stability of the upper structure, it is necessary to monitor the deformation of the column to ensure that the inclination angle of the column is within the allowable range. The non-contact measurement and high-precision point cloud data acquisition was carried out by the total station scanner used waveform digital ranging technology. During the acquisition process, the three-dimensional coordinates of each observation station were calculated by the rear intersection method, and the observation data was unified into a coordinate system. Data registration avoided the transmission of observation errors. This paper proposed a method for calculating the tilt deformation of the column using the point cloud. After collecting the two phases of the point cloud data, the deformation was calculated based on the true pair of points, and the point and surface optimization algorithm was used to reduce the error, and the tilt angle of the column was calculated. Finally, a simulation test of the tilted deformation of the column was designed to verify the accuracy of the deformation calculation method. The test results show that the actual inclination angle is 0°16'49", the calculated inclination angle is 0°16'57", the algorithm error is less than 20', which meets the requirement of deformation monitoring in high-rise structure. Therefore, the deformation calculation method can be applied to the field of column tilt deformation monitoring.

Due to the randomness of concrete carbonation process, the results obtained by the existing carbonation depth prediction models are difficult to characterize the actual carbonation status of in-service concrete structures. Therefore, combining the existing stochastic carbonization model with the actual measurement information of the carbonization depth of in-service concrete structures, a calculation method of a priori distribution hyper-parameters was given when the mean and variance of carbonized population samples were unknown. A Bayesian random model for the carbonation depth of in-service concrete structures was established. Taking the measured concrete carbonation depth of spillway pier and other structures of Yanshan Reservoir as an engineering example, the results show that the Bayesian random model can better represent the actual carbonation condition of in-service concrete structure.

In order to explore the relationship between macro and micro characteristics of hybrid fiber reinforced concrete under freeze-thaw cycles, rapid freeze-thaw cycle tests were carried out with freeze-thaw cycles and fiber volume content as variables. The test results show that under different freeze-thaw cycles, the compressive strength has a positive correlation with air content, bubble spacing coefficient and average chord length of bubbles, and a negative correlation with specific surface area of pores, while the freeze-thaw damage and pore parameters have an opposite law, and they all change approximately linearly; The larger the freeze-thaw cycles, the lower the compressive strength, the greater the freeze-thaw damage, the greater the air content, the bubble spacing coefficient and the average chord length of bubbles, and the smaller the specific surface area of pores; The incorporation of hybrid fibers optimizes the pore structure and improves the frost resistance.

In order to study the deformation and internal force of concrete lining structure of expansive soil trapezoidal channel in northern Xinjiang, indoor test and numerical simulation were used to calculate expansive deformation of foundation soil. Based on the beam theory of elastic foundation, a mechanical model was established to calculate the deformation and internal force of concrete lining slab. The deformation and internal force of concrete lining slabs were calculated and analyzed after the operation of the channel with the initial moisture content of the foundation soil being 6%, 9%, 12% and 15%. The results show that the deformation and internal force of the concrete lining plate increase with the decrease of the initial moisture content of the foundation soil. When the moisture content of the foundation soil is 6%, the maximum expansive deformation of the channel floor and slope plate can reach 3.48 cm and 3.94 cm. When the initial water content is constant, the expansion reaction force is the largest at the foot of the slope, and the displacement and bending moment are the largest at the middle of the bottom plate. The displacement of channel slope plate is the largest at one third of the slope foot, and the bending moment is the largest at one sixth of the slope foot. Finally, according to the research results, two engineering measures of "anti-seepage and moisturizing" were proposed.

In order to study the applicability of recycled aggregate in hydraulic asphalt concrete, the mix proportion test of recycled aggregate hydraulic asphalt concrete was carried out, and its mix proportion parameters were determined through uniaxial compression, splitting test and permeability (porosity). The asphalt aggregate ratio is 7.0%, the grading index is 0.37, the filler content is 13%, and the replacement rate of recycled aggregate is 50%. The recycled aggregate was modified with modifiers of different concentrations. The water absorption, apparent density, crushing index and adhesion of the recycled aggregate were analyzed to determine the modifier concentration that meets the test requirements. The modifier concentration in this test is 10% of water glass and 12% of silane coupling agent. Based on the above research, the applicability of recycled aggregate in hydraulic asphalt concrete was studied through water stability coefficient, thermal stability coefficient and permeability coefficient. The results show that the application of recycled aggregate in hydraulic asphalt concrete can meet the requirements of the specification, which can provide a reference for the popularization and application of recycled aggregate in hydraulic asphalt concrete.

In order to study the uniaxial tensile behavior of autoclaved aerated concrete blocks (AACB) in static state, the uniaxial tensile test of AACB with different densities was carried out. The tensile failure characteristics and failure mechanism of AACB were analyzed. The change rules of its tensile strength and elastic modulus under different densities were discussed, as well as the relevant formulas of the relationship between uniaxial tensile strength and porosity, compressive strength and splitting tensile strength. The experimental results show that the tensile yield strength and elastic modulus of AACB increase with the increase of density, but the tensile yield strain decreases gradually. The macroscopic failure of AACB under uniaxial tension is mainly controlled by the tensile damage mechanism of the material. It shows obvious brittle failure characteristics. Based on the ideal prediction model of porous materials and the regression analysis of test results, the semi-empirical formula and correction coefficient of AACB uniaxial tensile strength and porosity under the test conditions were fitted. The conversion relationship between AACB tensile strength and its compressive strength and splitting tensile strength was proposed.

In view of the problem that the compaction coefficient of cement improved silty fine sand road in Gobi area is difficult to meet the standard after the completion of rolling inspection as an engineering material, after comprehensive analysis, it is found that the timeliness of cement improved silty fine sand is not considered in on-site construction and inspection. Through the design of compaction test and unconfined compression test of cement improved silty fine sand under different delay time, the influence of delay time on the compaction characteristics and strength characteristics of cement modified silty fine sand was analyzed. Considering the strength change of Subgrade in seasonally frozen area after freeze-thaw cycle, the freeze-thaw cycle test of cement modified silty fine sand under the influence of delay time was designed. The results show that with the increase of delay time, the maximum dry density of cement modified silty fine sand first increases and then decreases, and the optimal water content first increases, then tends to be flat and then increases; The saturated 7 d unconfined compressive strength and the strength after freeze-thaw cycle decreased gradually with the increase of delay time; The structure formed by cement hydration inside admixture has been destroyed after being rolled and formed, reducing the cement effectiveness.

The rise and fall of reservoir water level will make the water storage environment of bank slope rocks different at different heights and water levels, and the types of water rock interaction are also different. Based on this, the deterioration test of rock mechanical properties of bank slope in water rock interaction zoning was carried out. The results show that the compressive and tensile strength of rock samples decrease with the increase of test cycle, showing a deterioration trend from fast to slow. With the advance of water rock interaction cycle, the shear failure characteristics become more and more obvious in the compressive and tensile tests of rock samples; The microstructure of rock sample gradually transits from dense to loose, porous and multi crack structure. Under different water rock interaction, the mechanical properties and microstructure deterioration degree of rock samples ranks thermal wet cycle > dry wet cycle > long-term immersion. The results can provide ideas for the long-term stability analysis of bank slope based on water rock interaction zoning.

Anti-dip layered rock slope is a common type of slope in hydropower engineering. Its stability is controlled by slope geometry, rock characteristics and structural plane properties. To reveal the influence of multiple factors on the stability of such slopes, taking the safety factor and displacement as dependent variables, the significance of six main factors, namely slope angle, slope height, rock inclination angle, rock thickness, rock quality and structural plane quality, was studied based on the approaches of discrete element modelling and orthogonal test design. Moreover, the deformation and failure laws of typical modes for anti-dip slopes were analyzed. The study can provide a reference for the optimal design of anti-dip layered rock slopes.