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Based on the overlapping tunnel of Tel Aviv Red Line Light Rail Project in Israel, this study established a three-dimensional numerical model by using Rhino6 and FLAC3D software on the basis of analysis of on-site monitoring data, to investigate the ground settlement and stratum displacement laws of shield overlapping tunnel at different overlapping angles.Results show that when the two tunnels gradually transit from horizontal to overlapping state, with the increase of overlapping angle of the two tunnels, the accumulated settlement at the measuring points in the middle of the two tunnels increases, but the accumulated settlement is not only affected by overlapping angle, but also closely related to the stratum traversing situation.Under the stratum condition of the project, when the overlapping angle is 60°, the accumulated surface settlement reaches the maximum because both tunnels pass through the loose reservoir K1 stratum.When the overlapping angle of the rear-built tunnel is less than 45° after excavation, the width of the settlement trough increases.When the overlapping angle is larger than 45° and smaller than 60°, the width of the settlement trough remains unchanged.The width of settlement trough decreases when the overlapping angle is larger than 60°.When the overlapping angle reaches 90°, the settlement trough is symmetrical on both sides.After excavation of tunnels on both sides, when the overlapping angle of the tunnels reaches 75°, the strata on both sides change the direction of movement.This research offer reference for the design and construction of overlapping tunnels.

TBM hob wear is an important factor that affects the TBM tunneling efficiency and construction cost.Different blade types differ in rock breaking efficiency and wear.By analyzing the rock-breaking mechanism of the arc blade wedged hob, this study established the calculation model of hob normal cutting, and analyzed the influence of hob edge angle on normal cutting force.This study then designed three kinds of hobs with different cutter spacing and three types of hobs with different blade for rock breaking tests in laboratory.Results show that the reasonable cutter spacing is 15mm, sharp blade is prone to be worn, the tooth-like blade, which has higher rock breaking efficiency and wear resistance, is better than arc blade.Combined with the actual situation of the project site, a new hob with wedge-shaped blade is developed, which are applied to inclined shaft TBM tunneling at engineering site.Results show that the wear rate of the new wedge-shaped hob is 20 % less than that of the conventional ones, and the service life of former is longer than that of latter.Under the same geological conditions, new wedge-shaped hob can reduce the number of hobs consumption and improve efficiency of tunnelling.The development and application of the new type successfully solved the problems of hob wear and frequent replacement of hobs in the TBM inclined shaft excavation.It can provide technical support for TBM long distance inclined shaft driving, which not only shortened the construction period, but also saved the construction cost.

With the development of informatization and digitalization, the transformation of intelligent manufacturing has become the focus. This paper builds an evaluation system based on the scientific evaluation method of the development level of smart manufacturing and the real demand situation. It establishes an evaluation model of intelligent manufacturing MES systems by combining the GA-BP algorithm. Then, a SeqGAN generative adversarial network is used to expand the real samples. The evaluation model was trained and validated by constructing a training model through the BP neural network, taking the sample data of evaluation indexes as the network input and the seven labels from Industry 1.0 to Industry 4.0 as the network output. The results show that the classification accuracy of the model is above 98%, and all of them have achieved good results. In the actual case evaluation, it is judged that the intelligent manufacturing MES system of Company Z is in the range of industry 3.0 to 3.5, and this result is very close to the manual evaluation of the factory field survey. The synthesis shows that the model is reasonable and effective and has important guiding significance for the evaluation of enterprise intelligent manufacturing MES systems.

Compared with the traditional "earth pressure balance" tunneling mode, the "air-pressure assisted" mode of shield tunneling has a more complex mechanism for maintaining excavation face balance, with significant differences in ground deformation and tunneling parameters compared to conventional full-chamber earth pressure balance tunneling mode. In order to quantitatively assess the stability of the excavation face under the air-pressure assisted tunneling mode and to determine a reasonable air-pressure setting, this study proposed an evaluation method for overall excavation face stability in the air-pressure assisted mode by using the limit equilibrium method, considering the spatial surface characteristics of the slip surface. Based on the Krabbe formula, considering the layering of the strata and the influence of groundwater, the formula for calculating gas loss was modified. In addition, a comparative tunneling test was conducted under different tunneling modes in the same strata condition, comparing the overall stability, air-pressure loss, ground settlement and tunneling parameters of the excavation face. The results showed that: according to the proposed overall stability evaluation method and the gas loss calculation method, the experimental section of this project met the overall stability requirements for air-pressure assisted tunneling. The selected air compressor had sufficient power for maintaining air-pressure stability in the strata, and the air-pressure setting met the requirements of engineering safety. Compared to the full-chamber earth pressure balance mode, the total thrust and cutterhead torque in the air-pressure assisted mode were reduced by 35% and 44%, respectively, while the advancing speed increased by 173% and energy consumption decreased by 66%. The air-pressure assisted tunneling mode resulted in a higher ground loss rate and relatively larger surface settlement. [ABSTRACT FROM AUTHOR]

Selenium is a vital trace mineral that is crucial for maintaining regular biological processes in aquatic animals. In this study, a four-week dietary trial was carried out to assess the impact of bio-fermented selenium (Bio−Se) on the growth and immune response of Chinese mitten crabs, Eriocheir sinensis. The crabs were randomly allocated to five dietary treatment groups, each receiving a different dose of Bio−Se. The doses included 0, 0.3, 0.6, 1.5, and 3.0 mg/kg and were accurately measured in basal diet formulations. The results showed the weight gain rate (WGR), specific growth rate (SGR), and survival rate (SR) in the 1.5 mg/kg Bio−Se group were the highest, and 3.0 mg/kg of Bio−Se has an inhibitory effect on the WGR, SGR, and SR. The activities of the immune enzymes, including glutathione peroxidase (GPX), superoxide dismutase (SOD), and acid phosphatase (ACP), of the hepatopancreas were significantly (p < 0.05) increased in the 1.5 mg/kg Bio−Se group, while they decreased (p < 0.05) in the 3.0 mg/kg feeding group compared to the 0 mg/kg feeding group. The concentration of maleic dialdehyde (MDA) exhibited the opposite pattern. Similarly, the mRNA expression levels of antimicrobial peptides (ALF-1, Crus-1, and LYS), ERK, and Relish genes were also observed to be the highest in the 1.5 mg/kg Bio−Se group compared with the other groups. Furthermore, the administration of 1.5 mg/kg of Bio−Se resulted in an increase in the thickness of the intestinal plica and mucosal layer, as well as in alterations in the intestinal microbial profile and bacterial diversity compared to the dose of 0 mg/kg of Bio−Se. Notably, the population of the beneficial bacterial phylum Fusobacteria was increased after crabs were fed the 1.5 mg/kg Bio−Se diet. In conclusion, the oral administration of 1.5 mg/kg of Bio−Se improved the growth efficiency, antioxidant capabilities, immunity, and intestinal health of E. sinensis. Through a broken-line analysis of the WGR against dietary Bio−Se levels, optimal dietary Bio−Se levels were determined to be 1.1 mg/kg. These findings contribute valuable insights to the understanding of crab cultivation and nutrition. [ABSTRACT FROM AUTHOR]

The floating of the shield segment will cause the segment to be misaligned and damaged, reducing the overall structural strength, waterproof performance and service life of the tunnel. On the basis of establishing the force model of the segments, by analyzing the force state of the segments, a theoretical calculation model of the segments floating is established. Taking the shield tunneling section ventilation shaft No.3-Caoqiao Station of Beijing Metro's New Airport Line as the engineering background, the abnormal rise of the segment was analyzed. By improving the performance of the synchronous grouting slurry, the floating amount of the tube segment was effectively controlled. And the slurry characteristics before and after the improvement were tested. Finally, based on the results of the slurry test and the theoretical calculation model, the floating volume of the tube segment was calculated. The results show that the theoretical calculation result of segment floating volume is consistent with the actual measured value. The theoretical calculation model in this paper has good accuracy. The segments float up a lot in a short time after it is released from the shield tail. Shortening the setting time of the slurry and improving its early strength are effective measures to control the floatation of the segments.

The aging of rubber will cause changes in the mechanical properties of materials, which in turn will cause waterproof failure.The section from the starting point of Beijing Metro Line 6 to Jin'anqiao is the first fabricated surface excavated tunnel in our country.It is of great significance to study the aging performance of the gaskets at the joints.The tunnel uses segments as the secondary lining structure, and EPDM gaskets as the waterproof material at the segment joints.In order to check whether the waterproof of the joints meets the durability requirements, an accelerated aging test was carried out on the rubber material of the gasket according to time-temperature equivalence principle, which predicts the service life of the rubber material.Due to the cumbersome calculation process of life prediction, the corresponding program was compiled to solve the problem of repeated trial calculation of parameters in the data processing.In addition, a numerical simulation of the stress of segment gaskets was carried out, and the influence of aging on the waterproof of the gasket was analyzed.It was pointed out that the designed water pressure of the gasket was increased to at least 1.75 times of the original one.

Based on the modified Loganathan theory, the longitudinal displacement of an existing tunnel caused by the ground loss in the process of shield crossing was studied. Timoshenko beam theory considering shear deformation was used to analyze the change of tunnel internal force and the amount of the dislocation between the adjacent rings. Based on the shear effect in elastic mechanics theory, the differential equation of tunnel longitudinal deformation was established and solved. After the bending deformation of Timoshenko beam, the difference between the beam cross-section of euler-Bernoulli beam which was not perpendicular to the neutral axis was analyzed. Furthermore, the variation of tunnel bending moment, shear force, and displacement between tunnel segments on tunnel shear stiffness and the ground loss ratio was studied. The results showed that the theoretical solution considering the shear deformation of the tunnel could predict the longitudinal deformation of the tunnel accurately. The proposed theory can correct the excessive internal forces such as bending moment and shear force without considering shear deformation and make up for the defect of unable to calculate the dislocation between the adjacent ring misalignment without considering shear deformation. The research results provide an effective method for predicting the influence of shield on existing tunnels.