Abstract:The anti-seepage effect of the cement-soil mixing pile impervious wall was studied, providing further optimization indicators for the design of impervious wall. The finite element model of the seepage flow was established and verified by the measured data. Different scenarios were simulated for the construction position and penetration depth of the cement-soil mixing pile impervious wall in the earth dam. The results shows that after the impervious wall is added, the seepage stability increases and the seepage control effect is obvious. The closer the cutoff wall is to the upstream of the dam body, the better the seepage stability of the dam body; the deeper the penetration depth of the cutoff wall, the better the seepage stability of the dam body. It is reasonable to place the cutoff wall in the middle of the dam body near the upstream, but considering the construction requirements in the actual project, the position of the cutoff wall should be properly moved back at the axis of the dam, which has little influence on the seepage flow.

Abstract:At present, the foundation pit engineering generally only cares whether the ground settlement value exceeds the monitoring and early warning value, and it lacks an effective method for short-term and real-time prediction of foundation pit surface settlement, which reduces the safety of the foundation pit. Using artificial bee colony algorithm to optimize the combination model of BP neural network can reasonably predict the settlement of the foundation pit surface. First, the gray correlation theory was combined to filter the input variables to improve the efficiency of the network structure. Then, the artificial bee colony algorithm was used to optimize the initial value of the BP neural network to realize the prediction of the cumulative maximum value and location of the surface settlement. Finally, ABC-BP model was compared with other common neural network prediction models to verify the validity of the model. It can be seen from the prediction and comparison results that the average relative error of ABC-BP model training and prediction results is 3.27%, and the root mean square error is 3.87, verifying that the model is effective.

Abstract:According to the characteristics of waste soil with high water content, a kind of recyclable solid drainage electrode combination suitable for super soft soil reinforcement was proposed. According to the spatial layout of the solid drainage electrode combination, the test is designed. The water discharge, water content and shear strength, settlement change, potential distribution, current change and energy consumption, the electro osmotic consolidation of soil under different conditions were compared and analyzed. The results show that:(1) after increasing the transverse drainage channel, the drainage consolidation path is shortened, and the middle part of the soil maintains a high potential level, which increases the maximum drainage capacity by 38% compared with the traditional vertical electrode; (2) The shear strength of the single-layer and double-layer combination is increased by 3.0 and 1.5 times respectively after increasing the transverse drainage body, and the soil moisture content is increased by 3.0 times and 1.5 times respectively (3) The concept of uniform energy consumption coefficient is introduced to reduce the energy consumption coefficient from 0.163 to 0.154 after adding horizontal drainage body, which reflects the advantages of three-dimensional drainage electrode combination.

Abstract:In order to solve the problem that the large amount of mud generated during the construction of the clay soil layer restricts the efficient and green construction of the project, the waste mud of the construction of a certain tunnel was selected, and anionic polyacrylamide (APAM), non-ionic polyacrylamide (NPAM) and polyaluminum chloride (PAC) were added respectively to carry out laboratory flocculation sedimentation test. The best flocculant and its optimal addition amount were obtained by combining with the flocculating mechanism of flocculant, and the field flocculation test was carried out. The results show that 0.5% APAM has good flocculation effect, which can quickly achieve the ideal flocculation, sedimentation, floating and sludge dewatering.

Abstract:In order to improve the shear strength characteristics of sand, it is aimed at sisal fiber reinforced sand composite material in this paper. The effect of fiber content, fiber length and dry density on the shear characteristics of reinforced sand was thoroughly studied by unconsolidated-undrained triaxial shear test so as to investigate the reinforcement mechanism of fiber-reinforced sand. The test results show that fiber reinforcement has little effect on the initial stiffness of sand. Appropriate fiber content and fiber length can form a three-dimensional network structure in sandy soil, which higher than that of unreinforced samples. It shows that fiber reinforcement can effectively improve the shear strength of sand. The shear strength of the composite material increases significantly due to the increase in the bite and sliding friction between the fiber and sand particles in the shear process. The increase of confining pressure on the effective contact area between fiber and sand results in the increase of shear strength and peak deviatoric stress. Sisal fiber reinforced sand can enhance the interfacial force between sand and improve the shear strength of sand.

Abstract:In this paper, natural palm fiber was used to reinforce clay. Through a series of unconfined compressive strength tests, the compressive strength characteristics of palm fiber reinforced clay at different rates of reinforcement and soil density were studied experimentally, and the reinforcement mechanism was analyzed profoundly. The results show that palm fiber can improve the compressive strength of clay to a large degree. When water content and soil density are constant, the compressive strength of reinforced clay increases with the increase of reinforcement ratio. When the moisture content and reinforcement ratio are constant, the compressive strength of reinforced clay increases with the increase of soil density. This can be attributed to that palm fiber and soil particles are interwoven and staggered to form a spatial network structure. At the same time, the bending deformation of palm fiber and soil in the process of the reinforcement can promote the close contact between the soil particles effectively, and consequently leading to the blocking of the soil displacement and improvement of the soil strength.

Abstract:In order to solve the environmental protection problem caused by the waste of filter press mud cake in the construction of mud-water balance shield, a new method of using filter press mud cake to modulate mud to improve the sand layer and muck was proposed. From the three aspects of mud density control, stability control and viscosity control, the press mud cake preparation mud test was carried out to determine the appropriate mud content for the improved sand and muck from the perspective of fluidity and permeability. The results show that the density of the mud prepared by the filter press mud cake should be between 1.29 g/cm³ to 1.34 g/cm³. Mixed with 3% to 5% sodium bentonite of the mud mass, the mud has high stability and viscosity. Mixed with the residue modulated mud with a mass of 6% to 10% can achieve a similar effect to the use of pure bentonite to improve the muck, and the amount of mud is greatly reduced. Therefore, it is feasible to use the filter press mud cake to modulate the mud and apply it to the improvement of the sand layer and muck, which is a new idea of energy saving and environmental protection.

Abstract:To overcome the shortcoming that the traditional component assembly model is difficult to describe the nonlinear characteristics of rock creep process, a new time-triggered nonlinear viscous component was proposed for series connection with the generalized Kelvin model. Then, the modulus attenuation equation of rock elasticity modulus during the rock creep process was introduced into the generalized Kelvin model to obtain a nonlinear creep model that can simulate the whole process of rock creep. Then, the one-dimensional and three-dimensional creep equations under different constant loads were derived. According to the general global optimization algorithm, parameter determination and model verification of the nonlinear creep model were performed by using the rock creep experiment curve of previous researches. The comparison between the theoretical calculation value of the model and the rock creep experiment curve shows that the nonlinear creep model is highly accurate and rational. It can better simulate the creep deformation of rock at different stress levels, and can provide certain reference value for carrying out similar researches in the future.

Abstract:Taking an embankment widening project as an example, the feasibility of self-compacting cement soil as the filling material of a new embankment was discussed in this paper. Based on the lab test data of excavated soil, numerical investigations on the settlement and differential settlement of the new and old embankments were carried out using the software Plaxis2D, and the stability of embankment slope was also analyzed. The influence of the new embankment slope ratio and geogrid laying was considered in the analysis. The results indicate that as the filling material of a new embankment, the self-compacting cement soil can effectively control the settlement and differential settlement, and laying geogrid can reduce differential settlement of the new and old embankments and significantly improve the stability of the embankment, the self-compacting cement soil is applicable in the embankment widening project.

Abstract:During the construction of the section from Yongjiang Road Station to Jinjiang Station of Hangzhou Metro Line 4, a wide range of liquidiable strata should be traversed. In order to reduce the potential risk of the tunnel destruction which could be caused by tunnel floating when earthquake acts, the buried depth of the tunnel was increased, so that part of the tunnel was located in the non-liquified soil layer. In order to study the influence of the local liquefaction formation range and burial depth on the seismic floating displacement of tunnel, and to evaluate the earthquake-resistance effect of the tunnel after adjustment, the finite difference software FLAC^3D numerical simulation and shaking table test were combined to carry out numerical analysis and model tests on the seismic uplift of tunnels in different liquefied soil layers and different buried depths. The results are as follows:the smaller the range of liquefied stratum is, the smaller the floating displacement is. When the tunnel is buried to 14 meters deep and the liquefaction ground layer of the tunnel is less than half of the tunnel area, the tunnel only slightly floats; Tunnels should avoid being completely in liquidiable formations, the seismic safety of the tunnel structure can be improved by combining the liquefied and non-liquefied stratum or increasing the buried depth.

Abstract:Based on the analysis of the engineering geological environment background of transmission iron tower foundation on Wufeng mountain in Zhenjiang, FLAC3D three-dimensional numerical simulation software and strength reduction method were used to analyze the deformation characteristics of the tower foundation slope under five working conditions of natural wind, strong wind 90°, strong wind 60°, strong wind 45ånd strong wind 0°. The stability coefficient of the tower foundation slope under each working condition was also calculated. The results show that the overall uneven settlement of tower foundation slope foundation under the conditions of natural wind, strong wind 90°, strong wind 60°, strong wind 45° and strong wind 0° are respectively:0.43‰, 0.66‰, 0.50‰, 0.33‰, 0.65 ‰. The slope stability coefficients are respectively:1.31, 1.25, 1.23, 1.23, and 1.18, indicating that the slope is in a stable state under five operating conditions. The stability of the foundation slope is relatively small when the wind is 0°.

Abstract:The influence degree of reservoir water level rise on reservoir bank slope is related to many factors, such as water sensitive stratum position, water level, sliding surface angle, etc. In order to study the influence of reservoir water level rising on slope stability during the impoundment process of Jingyugou reservoir in Bailuyuan, 51 slope profiles in the reservoir were counted and classified according to the slope evolution, stratum sructure, and the relationship between reservoir water level and stratum. The slope in jingyugou can be divided into tertiary sandstone mudstone slope, loess sandy mudstone gentle slope, loess sandy mudstone steep slope and eluvial soil sandy mudstone gentle slope. Four typical slope types were selected to establish the geological model, and Morgenstern price method was used to calculate the stability coefficients of the slope types in the process of reservoir water level rising. The results show that the stability coefficient of the tertiary mudstone slope, loess sand mudstone steep slope, loess sandy mudstone steep slope and eluvial soil sandy mudstone gentle slope in whale ditch is higher than the design safety factor of water conservancy and Hydropower Engineering Slope under any reservoir water level conditions. Due to Q_2-3 loess covering the whole slope, the stability of loess sandy mudstone gentle slope is poor. In the process of reservoir water level rising, the decline rate of stability coefficient is large, which is easy to form landslide and reservoir collapse. The calculation shows that the sliding volume of loess sand mudstone gentle slope under dangerous water level accounts for about 13% of the total sliding volume in the reservoir area.

Abstract:In view of the complex construction site environment and the problems of the YOLOv3 helmet wearing detection algorithm such as low accuracy and poor robustness, an improved YOLOv3 helmet wearing detection algorithm was proposed. The K-means algorithm was used to cluster out anchor boxes, so as to improve the network output scales. The residual block was introduced at the output to form a residual module; at the same time, the classification loss function was improved to balance the influence of positive and negative samples and difficult and easy samples on the model. In order to verify the effectiveness of the method, it was verified on the NVIDIA GTX1660Ti. The experimental results show that the mAP of the improved YOLOv3 helmet wearing detection algorithm increase by 4.84%, the detection ability of occluded targets and small targets is improved, and the model has strong robustness.

Abstract:Superhydrophobic surface can effectively inhibit frosting, but its application in the scale of heat exchanger and the study on its anti-frosting/defrosting behaviors are relatively lacking, which limits the application of superhydrophobic modification technology in solving the frosting problem of air source heat pump. In order to get the anti-frosting/defrosting performances of superhydrophobic heat exchanger, fin-tube heat exchanger with superhydrophobic surface was prepared integrally in this paper by etching bare unit in solution and then surface fluorinating. A frosting/defrosting experimental system was constructed to study the frosting and defrosting processes on heat exchangers with different surface characteristics. Experimental results showed that the frost mass on the superhydrophobic unit was reduced by 18.0% and 38.6% compared with that of the hydrophilic and bare units, when frosting 60 min under the same experimental conditions. In the aspect of defrosting, because of the direct peeling of the frost layer from fin surface, the superhydrophobic unit had short defrosting time and low defrosting energy consumption.

Abstract:The dynamic aging process of Al-Cu-Mg-Ag new heat-resistant aluminum alloy was subjected to pre-aging, rolling deformation at intermediate temperature and final aging. The influence of the dynamic aging on the mechanical properties and microstructure were explored by the hardness test, tensile performance test, and combined with metallographic microstructure analysis and transmission electronic microscopy (TEM) analysis. The results show that dynamic aging can increase the age hardening rate of the alloy. As the amount of deformation increases, the peak aging time of the alloy decreases and the peak hardness increases gradually. Dynamic aging can change the morphology of the grains. The aspect ratio of the grains increases with the increase of the deformation amount, more dislocations generate and the number of the strengthening precipitations with finer size increases, leading to the larger strength of the alloy. The sample with a 50% deformation has the largest tensile strength and yield strength of 527.4 MPa and 467.0 respectively, and its elongation remains at a relatively high value of 9.1%.

Abstract:Aiming at the problem of how to reasonably and accurately evaluate the credit of the borrower based on the unbalanced credit data, a new method for evaluating the personal credit risk was proposed. Firstly, the personal credit risk assessment index system was constructed, and in order to analyze the importance of each characteristic of the data, IV values of the credit characteristics of the data were calculated with IV model. Secondly, combining with fuzzy mathematics theory, a membership function based on the heterogeneous class hyperplane was designed. At last, combining the traditional support vector machine (SVM), a fuzzy support vector machine (FSVM) based on the heterogeneous class hyperplane was constructed. The results show that IV values of four indexes of personal loan credit risk assessment:, namely the available amount ratio, the number of overdue 30 to 59 days, the number of overdue 90 days or more, and the number of overdue 60 to 89 days are all more than 0.3, which are of great importance, indicating that they have a great impact on the credit assessment of the lender. The constructed membership function can provide different weights for different samples, and can reflect the importance of different samples. The constructed FSVM based on the heterogeneous class hyperplane can effectively improve the accuracy of estimating credit risk for personal loans, which shows the feasibility and the effectiveness of the proposed method.

Abstract:With hypoallergenic protein, microencapsulated oil and compound glycogen as raw materials, a kind of hypoallergenic nutritional meal package was developed. The particle characteristics, preparation characteristics and subjective and objective sensory characteristics of the powder were evaluated and studied on meal package.The meal package of color, smell, taste, and organization state after preparation were analyzed by fuzzy mathematics. The basic characteristics of the meal package were evaluated from the uniformity, dissolution stability and wettability of meal powder. The results shows that there is a correlation between the particle size distribution of the meal powder and the reconstituability of meal package. The particle size of fine powder (0~30 μm, 0~50 μm, 0~100 μm) is negatively related to the reconstituability of meal replacement, while that of coarse powder (200~500 μm) is positively related to the reconstituability of meal replacement. That is, with a continuous increase of the particle size of fine powder and the wetting time, its reconstituability is decreasing, and with a continuous increase of the particle size of coarse powder and the wetting time, its reconstituability is increasing. The particle size of meal powder has a positive linear correlation with the sensory score of the meal package. Within a certain range, with the continuous increase of particle size, the sensory score is continuously strengthened, and the product quality is better. This evaluation system provides a theoretical basis for improving the processing technology of hypoallergenic nutritional meal package.