Rehabilitation project of the Dabanshan highland road tunnel

The rehabilitation project of road tunnel in highland area and cold region is an important and worthy exploring research field. The development of the defects of crack in the liner, water leakage, structural deterioration and frost defects for Dabanshan road tunnel are studied. After an insight into the cause and development of tunnel defects, the water leakage and frost damage are considered as the root of defect, so restoration of drainage system and the reinstallation of cold prevention system are the focuses of the rehabilitation project. For consideration of safety, cover arch is installed for the tunnel structure enforcement as well. Results indicate measures in Dabanshan road tunnel rehabilitation project are effective for road tunnel of high altitude and tunnel in cold region.     

Analysis on the influence from rectangle cavity behind the lining to the primary support of tunnel

In process of the tunnel construction throw New Austrian Tunnelling Method, the result of smoothwall blasting to rock tunnel is not good, there are more and more cavities produced behind the lining. On the basis of engineering project, this paper makes the three-dimensional elastic-plastic analysis throw numerical simulation, discusses the stress-strain behavior of primary support when there is a different size of rectangle cavity behind the lining. In addition the safety factor of tunnel is calculated with cavity based on the strength reduction finit element method. This factor is compared with the factor of health tunnel. The stability of tunnel structure system is estimated through the linear regression analysis between stress of lining and safety factor.     

Effects of Radon Exhalation by Ventilation Styles in the Over-broken Granite Tunnel

The regularity of radon exhalation is affected by the weather and the ventilation in the over-broken granite tunnel. Based on the calculation model of radon exhalation in tunnel, some experiments have been carried out to analyze the variation of the radon exhalation in natural ventilation, blowing and exhaust conditions separately. The result showed that there is a linear relation between the radon exhalation and the natural ventilation, the temperature outside the tunnel also works as the same. It also shows that in the same condition of the tunnel's air flux and the outside temperature,the radon exhalation in exhaust case is 63% higher than the blowing case. When the temperature outside is high works in tunnel should avoid, and the blowing ventilation could be an effective way for reduction of radon concentration.     

Influence of Location and Form of HE-charges on the Air Blast Pressure Inside the Tunnel

In order to understand clearly to the influence of location and form of HE-charges on the air blast pressure inside the tunnel, based on Hopkinson scaling law, attenuation of air blast peak pressures in long tunnels due to HE-detonations in the case of different location and form at the tunnel entrance is simulated with the dynamic finite element software of LS-DYNA. The results are compared with other experimental methods. The results indicate that the influence of location and form of HE-charges is significant near the HE-charges. As the distance from the HE-charges larger and larger, the influence of location of HE-charges is smaller and smaller, but the influence of form of HE-charges is larger and larger. The methods and data presented can be refereed in similar engineering and determination of loadings upon protective doors.     

Analysis and Simulation of the Highway Tunnel Fire Contamination

A one-dimensional contamination diffusion model for tunnel fire is presented. Based on this model, a highway tunnel fire within a short time course was simulated and analyzed. Compared to the test results, the simulation result demonstrates that the model is feasible. In the end, it suggests a formula for highway tunnel fire contamination. The author hopes that this analysis will be available as the foundation of highway tunnel fire control.     

Study of Intellegent Mehod on the Tunnel Supporting Time

As an useful perspective,the NATM has gone into many hands of the tunnel and underground structure designs and constructions.But the supporting time,which determines the tunnel's support quality,is usually determined by the engineer's experience.What's more,different engineers have different decisions on the supporting time,so the construction project quality would vary greatly.In this thesis the neuro-fuzzy inferential system was set up to gain the supporting time,which can make a good use of the experience of the engineering projects.The result suggests that this system has a good accuracy and is useful in the engineering practice.     

Model test of influence of excavating new interchange tunnel on existing tunnel

In order to analyze the influence of construction of new interchange tunnel on existing tunnel, a three-dimension model test of interchange tunnel is carried out with the system of structure and surrounding rockmass of highway tunnel. Existing tunnel’s surrounding rock pressure, internal displacement and supporting internal force are measured. The results show that, firstly, excavating new tunnel has obvious influence on section Ⅰ of existing tunnel, and has little influence on section Ⅱ.All surrounding rock pressure keeps decreasing and arch bottom surrounding rock’s stability reduces. Secondly, crown and hance internal displacement manifest tensile deformation, and the deformation at crown is bigger than that at hance. Thirdly, exiting tunnel’s supporting axial force keeps increasing and supporting moment keeps decreasing. Finally, excavating new interchange tunnel has obvious influence on exiting tunnel’s surrounding rock pressure, internal displacement and supporting internal force when adjacent space is 0.25D, and it indicates that interchange tunnel’s adjacent space should be no less than 0.5D.     

Research of Wind Load on the Surface of YingLi Building in Chongqing

Considering the complicated distribution of wind load on the surface of the tall building, the 1:300 scale model test of YingLi building is completed in the No.2 environment wind tunnel, which belongs to the State Key Lab of Environmental Engineering College, Beijing University. Based on the calculation and analysis of the test results, this paper discusses the coefficient of wind-induced vibration and shape coefficient of wind load , gives the maximum and minimum value of surface wind load, which can be used for the wind resistant design and insure the security of the building under 100 years return period wind load.     

Theoretical calculation and monitoring on rock pressure of shallow-buried bilateral bias neighborhood tunnel

In order to research the tunnel rock pressure and its distribution, the mechanical model of tunnel rock pressure of shallow-buried bilateral bias neighborhood tunnel is set up based on series assumptions. The calculation theory of tunnel rock pressure is deduced, in which the construction processes of twin tunnels can be considered. Furthermore, the contact pressure between tunnel lining and surrounding rock is monitored on site at Zuan Qianmen Tunnel of Xinbao expressway, and the change law of contact pressure corresponding with time and construction processes is obtained. Meanwhile, the comparison analysis has been made between field monitoring value and theoretical value, and the result shows that the tunnel rock pressure’s mechanical model and calculation theory of shallow-buried bilateral bias neighborhood tunnel is rational, which will provides the theory foundation to tunnel design and tunnel rock pressure calculation of shallow-buried bilateral bias neighborhood tunnel.     

Explosion dynamic response of soil surrounding tunnel with curve wall

It’s significant to obtain the mechanic laws and weak parts of soil tunnel, and the most likely failure elements under the explosion shock action to prevent terrorist attacks which can cause tremendous loss of human life and property and collapse and damage of many buildings and construction. Therefore, numerical simulation for soil tunnels is carried through the explicit dynamic finite element program ANSYS/LS-DYNA, and the time-history curves are discussed about the soil surrounding tunnel under explosion action. The dynamic response of soil tunnel under the explosion action is analyzed by establishing finite element integral model of soil tunnel dynamic analysis and comprehensively considering the solving method of nonlinear dynamic equation, the selection of different material models, the method of explosion shock wave input and the convergence and realizing factors of fluid-solid coupling effect. Thus, a reference for antiknock design of tunnels is presented.     

Analysis on the Deformation and Stress Control Measures of Metro Tunnel Near a Foundation Pit

It has become a very common phenomenon that the influence of pit excavation to the adjacent environment, what corresponding measures should be taken in design and construction to ensure the safety of construction in process and existing has become a key part. This Paper analyses the influence of pit construction to adjacent tunnel by using the finite element software plaxis. The analysis results show that strengthening the palisade structure stiffness and partitioning symmetric excavation can significantly control the deformation of the existing tunnel. The design and construction of the engineering can ensure the safety of the existing tunnel compared with the conventional construction methods, and it also shows that preliminary analysis of influence to the adjacent underground building before pit excavation is very necessary.     

Influence on new tunnel mechanics behaviorinduced by construction about adjacent spacing

This paper takes Chongqing Two-River Tunnel as the research background, based on the system for structure and surrounding rockmass of the highway tunnel, conducts a three-dimension model test about forked tunnel with different altitude to study new tunnel’s mechanics behavior induced by construction, and uses numerical simulation to analyze model domain. The results show that the displacement on new tunnel’s left hance is larger than the displacement on its right hance. Left hance displacement is larger than hance displacement of the single tunnel, and the right hance displacement is less than hance displacement of the single tunnel. The trend of hance displacement and crown settlement with different adjacent spacing is got. Normalizing hance displacement and crown settlement of model test, the relation between displacement and adjacent spacing is disclosed. The hance displacement and crown settlement gained by numerical simulation is close to the converted result of model test, which indicates that the model test data is consistent with the result of numerical simulation.     

Neural Network Model for Predicting the Transformation Tendency of the Stress on the Surrounding Rocks of Tunnel

The stress on the surrounding rocks affects severely the stability of tunnel. To estimate the stability of tunnel needs the transformation tendency of the stress on the surrounding rocks. After the transformation tendency of the stress on the surrounding rocks and the factors affected it are analyzed, the neural network model for predicting the stress on the surrounding rocks is created. The model is applied successfully to predict the change of the stress of the Guanyingyan tunnel in the Qiwan expressway, which proves that it is feasible to predict the stress on the surrounding rocks with the neural network model. The method is convenient and correct.     

Dynamic Prediction Analysis of Surrounding Rocks Stability for Non-symmetric Double-Arch Highway Tunnel

During the construction of non-symmetric double-arch rock highway tunnel, the complicated geological condition may affect the safety of the constructor and the engineering quality. In this paper, two treatment methods are put forward. At first, the site monitoring of surrounding rock displacement must be carried out, then, BP neural network is applied in predicting the displacement of surrounding rock based on the learning sample of measured value, so the stability of surrounding rocks may be analyzed and forecasted. During the analysis of BP neural network, the effects of joint and fracture of surrounding rock on displacement can be comprehensively considered, comparing the predicted values of displacement with those by FEM. The results show that not only the predicted error of BP neural network is relative small, but the predicted values of surrounding rock displacement are close to measured ones. So, the predicted values of BP neural network are reliable and may guide the engineering construction in site.     

梨树大棚栽培棚内外温湿度环境变化规律和物候期研究

为梨大棚栽培技术的制定提供参考依据,对梨树大棚栽培棚内外空气温度、空气相对湿度、土壤温度以及梨树物候期的变化特点进行比较。结果显示：（1）随季节的变化,气温和地温均呈逐渐上升趋势, 6月之前棚内气温、相对湿度和地温均高于露地,且昼夜温差大于露地,6月起棚内外温度差异不显著。（2）棚内栽培‘翠冠’和‘黄冠’梨萌芽早,但落叶晚,整个营养生长期分别为242天和231天,分别比露地长27天和37天。（3）大棚栽培的‘翠冠’和‘黄冠’梨开花期比露地皆提早18天,且花期比露地长2天。（4）棚内栽培条件下,‘翠冠’和‘黄冠’梨采收期分别提早13天和14天,而果实发育期比露地分别长5天和4天。研究结果表明,大棚条件下温湿度高,开花期提早,果实成熟期提前,南京地区可进行梨保护地栽培。     

改进塑料薄膜小型拱棚温、光条件的措施及其效果

通过观测、考察拱棚在春前加强保温,秋后提早盖苫蓄热是目前提高内部气温和土壤温度、延长应用时期的主要方法。由于受生产条件的限制,常因覆盖物遮阳在北侧形成弱光带,这是亟待改进的问题。     

Research on the Body Coefficient of Complicated Tall Buildings

Considering the complication of the coefficient of wind-induced vibration for tall buildings,the scale 1:300 model test of Ying Li Building is completed in the second wind tunnel of Beijing University.Based on the calculation and analysis of the test results,the static and dynamic wind pressure acting on the building can be obtained and the value of the coefficient of wind-induced vibration for this tall building can be solved directly,thus a new way is laid for the research of complicated tall buildings.     

高超声速风洞进气道流量系数测量精度影响因素研究

进气道是飞行器动力装置的重要组成部分,准确测量进气道流量系数是进气道风洞试验的重要内容。对来流马赫数Ma=4.5,5.0和6.0状态下皮托管进气道开展流量系数测量研究,通过对比理论值和实测值,获取各状态流量系数修正系数。试验结果表明,随着来流马赫数增加,进气道流量系数与理论值偏差较明显,并逐渐增大。超声速风洞试验通常认为测量截面总温与来流总温相等,通过对测量截面总温与来流总温偏差以及测量截面流场畸变情况的分析,判断测量偏差主要是由测量截面总温等于来流总温的假设导致的。在高超声速风洞试验中,由于模型壁面热交换的存在,测量截面总温低于来流总温,进气道流量系数测量时需要进行总温修正,以提高流量测量精度。      

实测确定公路隧道洞外景物亮度的方法

分析比较了查表法、环境简图法和黑度法3种确定洞外亮度的方法,发现3种方法均未完全考虑隧道所处区域的环境和光气候条件。为了能快速准确地确定隧道洞外景物亮度,以从莞高速公路的7座隧道为测量对象,通过现场实测,建立了洞外景物亮度与水平面照度之间的关系。在对当地光气候数据进行统计分析的基础上,确定隧道洞外景物亮度标准值、东莞地区隧道洞外典型景物亮度设计参考值,并得到了东莞地区4个朝向隧道洞外典型景物亮度值。     

Smooth blasting design and optimization of large spanurban highway tunnels

Vibration resistance can be incorporated into blasting designs to avoid damages caused by the excavation of large span tunnels in busy urban areas, but only by basing excavation design schemes on actual situations. In view of the actual situation in the Jahua tunnel in Chongqing, P. R. China, research was conducted to identify a relevant explosion scheme. The research was based on theoretical analysis and in situ testing. Face step excavation was considered in the broadening band A, and upper drift excavation was adopted in broadening bands B, C, D and E. We simultaneously proposed selection criteria for smooth blasting parameters and the construction layout of broadening band B. Based on a regression analysis of the blasting vibration monitoring results, a spread orderliness of blasting vibration was drawn. Explosion parameters optimization measures were put forward, selected from the maximum charge quantity, millisecond blasting, reasonable blasting time difference, and the excavation plan. Field testing achieved satisfactory results. These findings will play an important role in guiding excavation blasting construction of tunnel projects and assuring the safety of ground buildings.