Abstract:Based on the theoretical derivation, the distribution law of the grouting pressure of the underground road during the construction of the shield tunnel in three-sided enveloped space was obtained. The reasonable grouting pressure was calculated and the influence of the grouting pressure on the structure of the underground tunnel was discussed. The results show that the grouting pressure can offset the structural deformation caused by the shield tunneling and even generate new additional deformation. When the soil loss rate is larger, the influence of the grouting on the structure of the underground road is greater.

Abstract:In order to study the influence of eccentricity rate on the mechanical properties of CFRP reinforced concrete filled steel tubular column, the finite element software ABAQUS was used to simulate the components with eccentricity rate of 0.3%, 0.6%, 0.9% and 1.2% respectively. The results show that with the increase of eccentricity, the tightening force of passive restraint decreases. Eccentricity has great influence on the load deflection curve of components, and the ultimate bearing capacity of components with high eccentricity is small. Different eccentricity has different effects on components with different slenderness ratios. When slenderness ratio is 28, the bearing capacity of components decreases correspondingly.

Abstract:Sloshing wave height of vertical storage tanks under earthquake action is one of the main criteria for tank design, and the wave height formulas of seismic codes for storage tanks at home and abroad are based on the theoretical formulas of first-order sloshing. Whether the wave surface vibration of vertical storage tanks under real seismic action involves the participation of higher order array is a problem needed to determine. In this study, the sloshing response of 10,000 square vertical storage tanks under earthquake action was analyzed by finite element software ADINA. The test results show that the sloshing wave height of vertical storage tanks is linearly related to the peak acceleration of input ground motion, and the ratio of the two excitation wave heights to the response peak acceleration keeps the same, and the influence of different liquid storage ratio on the sloshing wave height and the first-order sloshing period is small. In addition,the location of the radial extreme point of sloshing wave height remains different under different earthquake motions. The closer the extreme point was to the core of the tank, the richer the mode of sloshing participation is, the more obvious the mode superposition is. It shows that the sloshing of liquid storage under earthquake is the result of multi-order mode superposition.

Abstract:The creep of the red layer side slope is remarkable, and the rock has strong creep characteristics. In order to reflect the whole process of the rock creep, the elastic strain, the viscoelastic strain and the viscoplastic strain of the rock creep were respectively described by the elastic body, the soft element based on the fractional calculus and the viscoplastic body based on the phase characteristic of the rock creep. The damage variable was added to the elastomer, the SN element was introduced to improve the fractional-order soft element, the modified elastomer and the non-unsteady viscous body and the viscoplastic body based on the fractional calculus were integrated, and a new constitutive model of the three-element creep damage was constructed. The triaxial compression and creep test of red-layer mudstone is carried out by the RLW-2000 three-axis rheological test system, and the typical creep data of the red and red sandstone in the relevant literature are cited, and the model is verified by three kinds of rock creep curves, and the rationality and applicability of the model are proved.

Abstract:Aiming at the impact of softening contact zones between the upper waste and the lower bedrock on its stability, in this paper, the finite element limit analysis method was used to establish the numerical model of dump slopes with softening contact zones. And then the stability of dump slopes under different landfill angles, dip angles of bedrock, thicknesses of softening contact zones, softening degree was analyzed. At last the feasibility of this method was verified by a concrete dump slope. The results show that the softening of contact zones and the landfill angles have a great influence on the slope stability, while the dip angles of bedrock and the thicknesses of contact zones have a relatively small influence under the same conditions. With the increase of the softening degree of the contact zones, the absolute attenuation rate of the lower and upper limit safety factors of dump slopes can reach about 50%. With the continuous soil softening of contact zones, the length of sliding surface of the dump slope passing through the softening contact zones increases gradually, and the total volume of the sliding body increases continuously. Due to the existence of softening contact zones, the lower soil mass in the dump slopes pushes the front edge of the slope foot and pulls the back slope body to slide, and finally forms the through sliding surface from softening contact zones to the top of the slope.

Abstract:Based on the results of the rheological test of monzogranites, the Biot coefficient was determined by cross-plotting method, the creep model based on permeation pressure damage was established on the basis of the generalized Bingham model, the creep parameters were determined by fitting the rock creep test data, and the parameters of the creep damage model were obtained. The creep constitutive equation of the model was deduced, and the data of the rock creep test were fitted with this model.The fitting results show that the model can not only describe the the decay creep and steady-state creep stage, but also describe the accelerated creep stage of the rock, thus proving the feasibility and rationality of the model.

Abstract:Based on the laboratory model test, the deformation of pile-supported embankment and the stress distribution of soil filling under the action of geogrid are studied. The effects of geogrid tensile strength and the number of layers of geogrid on the vertical displacement of soft soil, vertical stress distribution of soil filling and pile-soil stress ratio are emphatically studied.The results show that the vertical displacement of soft soil decreases with the increase of geogrid tensile strength and the number of geogrid layers.Under the action of different layers of geogrid, the vertical stress of fill soil varies greatly with the height of fill soil.Considering the soft soil deformation of pile-supported embankment and the transfer degree of filling load to the pile top comprehensively, the effect of geogrid under the study condition is understood, which can provide a basis for selecting suitable geogrid tensile strength and layers in embankment engineering.

Abstract:In order to study the effect of the replacement rate of recycled coarse aggregate on the compressive property of broken pebble concrete and the supersonic velocity of compressed concrete under different replacement rates, the standard cube test blocks with the replacement rates of 0%, 15%, 30% and 45% of recycled coarse aggregate were prepared for compressive property tests on days 3, 7, 14, 28 and 45 and compressive stress-ultrasonic velocity tests on days 28. The results show that with the increase of the substitution rate, the compressive strength of the cubes in each age increases first and then decreases. The trend is especially obvious at 3 days, and the trend becomes smaller after the age of 28 days. With the increase of compressive stress coefficient, the ultrasonic sound velocity at each substitution rate increases first and then decreases. When the compressive stress coefficient is 0.2, the maximum value is obtained. For the same compressive stress coefficient, with the increase of substitution rate, the variation trend of ultrasonic velocity is similar to that of compressive strength.

Abstract:With the goal of improving service levels, given the known origin destination(OD) distribution of bicycle trips in a specific area, an optimization method for urban bicycle network parameters mainly referring to bicycle lane spacing and bicycle lane width was proposed. Several test scenarios were built by different combinations of key design parameters, and Cube simulation model was used to test and analyze the effects of these scenarios. Level of service indicators such as total travel time, average speed and road saturation were obtained. The recommended key design parameters can be obtained by comparing the results. Multivariate analysis of variance was used to compare the effects of two key parameters. It is found that increasing lane width could significantly improve the level of service of bicycle network. Finally, the planning and design strategy for improving bicycle travel conditions is put forward.

Abstract:The wind environment of the residential district is an important factor to measure the living space. Taking the planning and design scheme of a residential area in Hefei as a sample, two schemes in the planning and design stage were selected, and the Airpak software was used for numerical simulation to analyze the wind environment of the two schemes under different wind field conditions in summer and winter. According to the current national standards, the evaluation indexes of wind speed and wind pressure at the pedestrian height of 1.5 m were evaluated, and the effect of building layout on the wind environment was summarized. It is concluded that building an open ventilation corridor can fully improve the ventilation effect of the residential area in summer. This paper aims to optimize the wind environment in High-rise residential areas, and create the theoretical guidance for building a healthy and comfortable residential district environment.

Abstract:In order to study the possible palace building shapes and practices of the No.2 rammed earth station in the ruins of the ancient city of Zhao State in Handan, through on-site investigation, sorting out the archaeological findings and historical data, analyzing the architectural forms and construction techniques of the king city of Zhao during the warring States period, the building materials and construction techniques used at that time were deduced and the No.2 rammed earth station was restored to a high-rise palace building with a mixed structure of civil engineering.

Abstract:By analyzing the measured data of hydrology and salinity in the North Passage of the Yangtze River Estuary in 2016, it is found that the salt water wedge exist and the salinity stratification is stronger during neap tide than spring tide. The Simpson potential energy was applied to study the temporal and spatial variation of the mixing and stratification of the North Passage, and the extreme value of potential energy anomalyat the upper and middle of North Passage appears at the high slack and low slack while it appears at the max flood and max ebb at the lower part of North Passage. The improved one-dimensional potential energy difference equation was used to analyze the spatial and temporal changes and corresponding relationships of tidal strain, estuarine circulation, river effect, and tidal stirring during the dry season in the North Passage. It is found that the trend of mixing and stratification of the water body is determined by the relative sizes of these four factors, and the mechanisms that affect the stratification changes during the spring and neap tide are tide stirring, estuarine circulation and river effect. It is found that the estuarine circulation is the main dynamic mechanism for promoting estuary stratification during flood tide; the river effect is large during the ebb, and the average tide effect is stronger than the tidal strain, which promotes the estuary stratification as a whole; the tide stirring in the spring tide is 1 to 2 orders of magnitude larger than the neap tide, which weaken the stratification. And the improved one-dimensional potential energy difference equation can better explain the mixing and stratification characteristics of Yangtze River Estuary.

Abstract:Taking the runoff data of 23 meteorological stations in the Huaihe River Basin(HRB) from 1951 to 2016 and the runoff data of the Bengbu hydrological station as the research objects, linear quasi-legal, sliding average and non-parametric MK test were used to analyze the characteristics of precipitation and drought in the HRB.The correlation between precipitation, drought and runoff and long-range memory was analyzed with the combination of R/ S analysis, Pearson and Spearman correlation coefficient. The results show that except for continuous wet days, the extreme hydrological index of HRB showed a significant increasing trend, and the abrupt years were concentrated in the 1950s and early 1960s. In the past 70 years, the annual drought frequency reached 21.2%, and the proportion of light drought was the highest. From the annual and seasonal scales, the winter drought is the most severe, and the annual and seasonal drought show a decreasing trend. There is a moderate correlation between precipitation and runoff over a maximum of 30 and 15 days. The precipitation and runoff in flood season and non-flood season are moderate and weak respectively. In the next 4 to 11 years, the maximum 30-day precipitation and runoff, the precipitation and runoff in the flood season and the non-flood season willnot show significant growth trends.

Abstract:In order to identify the characteristics of Dong Zhizhen's precipitation and predict the trend of annual precipitation, the Mann-Kendall (MK) test and Morlet wavelet transform were used to analyze Dong Zhizhen's annual precipitation from 1959 to 2016. The result shows that there is a slight increasing trend of the annual precipitation in the Dongzhi Tablelandand there is a abrupt change in the annual precipitation, the starting years of which are 1962, 1970, 1985, 1995, 2003 and 2009 respectively, with the interval of about 10 years. The annual precipitation is mainly affected by the scale periodic fluctuation of 2, 4 and 8 years, and the first main cycle is 8 years.The annual precipitation alternates significantly between wet season and dry season in the whole time domain of the study.The annual precipitation with an eight-year cycle takesa cyclical pattern of rise and fall.

Abstract:In order to effectively predict the air quality indicators of heavily polluted days with small sample size and discontinuous time series, The data grouping GM(1,1) model with fractional order accumulation (DGFGM(1,1)) was used to predict AQI and the daily concentrations of PM_2.5, PM₁₀, NO₂ for December 28, 29 and 30 in Handan. The MAPE of the AQI, PM_2.5, PM₁₀ and NO₂ predicted by DGFGM(1,1) model were 2.89%, 3.28%, 3.83% and 3.23%, respectively, indicating that this model has a high prediction accuracy. The prediction results demonstrate that under the current governance measures, the occurrence of heavily polluted days is still inevitable, and the concentration of some air quality indicators will increase rather than decrease. Except for the daily concentrations of NO₂ on December 30 during 2018 to 2019, the concentrations of all air quality indicators exceeded the grade II standard of Chinese Ambient Air Quality at other times. Local departments should pay attention to the prevention and treatment of extremely heavy pollution days, so as to comprehensively improve the quality of atmospheric environment.

Abstract:In view of soil deformation in land subsidence, compression-rebound tests of different soils (sand, silt and clay) in different states were carried out. Based on the study of soil deformation mechanism of relevant soils, the compression-rebound characteristics of different soils were studied. The main conclusions are as follows: the compression deformation of sand is the most significant, followed by silt, and finally clay. The deformation of sand is characterized by small initial deformation and large later deformation. On the contrary, the deformation of silt and clay mainly occurred in the early stage. The deformation of three kinds of soil is mainly irreversible, and the deformation of clay has obvious hysteresis. The deformation of sand mainly comes from the remolding of sand structure, clay comes from the remolding of structure and redistribution of water, and silt is similar to clay.

Abstract:In order to improve the accuracy of crop identification and expand the scope of data application, two pieces of GF-1 data with 16 m spatial resolution and 23 pieces of MODIS data with 250 m resolution were used as data sources. First, the supervised classification of GF-1 and the construction of MODIS NDVI time series were carried out. Then, the decision tree model was constructed by using the supervised classification results and time series data characteristics to identify the main crops in Shijin Irrigation Area. The overall accuracy of extraction reaches 93.13%, which is more than 10% higher than the result of supervised classification. The results show that the method can not only recognize the spatial and temporal distribution information of crops, but also give full play to the advantages of the data.

Abstract:In view of promoting the research and development of precision drugs for the novel coronavirus COVID-19,this paper focuses on the basic steps of COVID-19 infection in human cells, such as viral surface protein binding to human cell receptor, viral penetration into cell membrane, viral uncoating, release and replication of viral nucleic acids, expression and maturation of viral proteins, new virus assembly. Based on these steps, it is expected that small molecule compounds, antibodies or antisense RNA fragments could be designed to prevent the key viral molecules such as Spike protein, RdRp polymerase, 3CL hydrolase and a variety of key RNA genes, so as to achieve the goal of accurate treatment of COVID-19 infection.