Site Monitoring Analysis of Influence of Excavation and Construction of a Unsymmetrical Loading Twin-Arch Tunnel

2014 ◽  
Vol 584-586 ◽  
pp. 2083-2086
Author(s):  
Ku Zhu Zhu ◽  
Zu Jian Wang ◽  
Zhi Gang Wang ◽  
Yuan Cheng Liu

Unsymmetrical loading twin-arch tunnel which has its own characteristics is different from the general separated tunnel. This paper takes a unsymmetrical loading twin-arch tunnel as the background, supervises the tunnel and clears up and analyzes the monitoring data. The results shows: (1) The subsidence of arch crown grows with section excavation, it diminishes gradually and tends to be stable in the initial stage of support and the complete stage of inverted arch. (2) The convergence pre-day of tunnel surrounding rock increases and becomes stable until the lower inverted arch has finished in the effect of unsymmetrical loading and excavation. (3) The surface position of tunnel midline is the most significant position of excavation influence. (4) Unsymmetrical loading makes the lining and middle wall become dislocated, and cracks and peeling phenomenon appears. These conclusions can provide reference for slope design, construction process and site monitoring for unsymmetrical loading twin-arch tunnel under similar conditions.

2019 ◽  
Vol 9 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Magdalena Kowacka ◽  
Dariusz Skorupka ◽  
Artur Duchaczek ◽  
Paweł Zagrodnik

AbstractThe work contains information on the implementation of surveying works in the road construction process. The aim of the research was to identify geodetic risk factors occurring at the stage of preparation of a construction project, the presence of which can greatly disrupt the undertaking such as the road construction. The research was carried out on the basis of expert knowledge, documentation obtained from various road construction projects and the analysis of disturbances at the initial stage of works.


2013 ◽  
Vol 353-356 ◽  
pp. 1604-1608
Author(s):  
Guang Bin Bai ◽  
Jie Zhao ◽  
Li Sheng Liu

Based on a subway tunnel construction, the construction method was introduced. The ground subsidence, crown settlement and convergence displacement caused by the cut tunnel are monitored during the tunneling construction and the results of monitoring data for them are analyzed. This technology wells to guide the tunnel-entering construction effectively and avoid the tunnel-entering construction process prone to landslides, thus ensuring the safety of the tunnel construction and will guiding the future construction.


2020 ◽  
Vol 198 ◽  
pp. 02006
Author(s):  
Nana Li ◽  
Yongqiang Zhou ◽  
Yanqiang Zhao ◽  
Guiju Li

In order to study the interaction between the left and right tunnels of suspension bridge tunnel-type anchorage, the finite difference numerical software is used to analyze the mechanical properties of the surrounding rock during the construction process. A numerical analysis model based on FLAC3D is established to analyze the stress, displacement and plastic zone changes of the surrounding rock of right tunnel anchor cavern during the construction of left tunnel anchor cavern. The right tunnel anchor cavern is excavated firstly, and then the left tunnel anchor cavern is excavated. The numerical simulation results show that the main displacement of the right tunnel occurs in the construction stage of the anchor plug body and the rear anchor cavern of the left tunnel. During the excavation of the left tunnel, the plastic zones of the left and right tunnel anchor caverns are only connected above the middle of the waist wall. Therefore, it is suggested that during the construction process, especially in the excavation stage of the anchor plug body and the rear anchor cavern, the area above the middle of the tunnel waist wall should be strengthened in time to ensure the construction safety.


2012 ◽  
Vol 204-208 ◽  
pp. 196-201 ◽  
Author(s):  
Jian Cong Xu ◽  
Yi Wei Xu

The parabolic-apex numerical back-analysis method (PNBM) was proposed to obtain such physical-mechanics parameters as Young's modulus and lateral pressure coefficient of surrounding rock by 3D FEM numerical analysis based on in-situ monitoring data. Taking Xiang-an Subsea Tunnel (located in Xiamen, Fujian Province, China) for example, adopting the PNBM using ABAQUS software, three dimensional elastic-plastic FEM-PNBM of tunnel surrounding rock was validated using in-situ monitoring data. The results show as follows: Using the PNBM, not only may high calculation precision be obtained, better meeting the demand of actual projects, but also more reasonable and reliable physical mechanics indices of surrounding rock such as Young's modulus and lateral confinement pressure coefficient, may be obtained. The applicability and the simplicity of this proposed method also support its usefulness.


2013 ◽  
Vol 353-356 ◽  
pp. 1555-1558
Author(s):  
Ke Wu ◽  
Ke Zhang ◽  
Cheng Jun Wang ◽  
Chuang Zhao

The deformation monitoring of surrounding rock and data processing in tunnel is the foundation and safety technical support of underground engineering information control and management. However, due to the special environment in the underground engineering construction, acquiring the deformation information of surrounding rock accurately and fast to assess the stability of surrounding rock is becoming one of the bottleneck problems for underground construction project information to be solved. According to the underground engineering projects, Based on the dynamic monitoring data processing and analysis, a set of underground engineering construction monitoring measurement data processing system is established, which can meet the acquisition of the monitoring measurement data, the arrangement of the measured data, data analysis and feedback, the monitoring data regression analysis.


2016 ◽  
Vol 8 (4-3) ◽  
Author(s):  
Tsau Kar Yen ◽  
Izran Sarrazin Mohammad ◽  
Maizan Baba ◽  
Rohaya Abdul Jalil ◽  
Nurul Nadiah Zainol ◽  
...  

The demand for green buildings in the property market is substantially increasing. The motivation for the investment on green buildings ranges from environmental concerns and social benefits to financial savings during the operational stage. However, these perceived benefits have been argued to be mostly theoretical and yet to be empirically proven. There is often a performance gap between the expected and the actual measured performance of green buildings once operational. Green buildings simply fail to perform as to what it was intended despite the thorough design and technological considerations put at the initial stage of their development. Hence, by reviewing various literatures, this paper targets to indicate and discuss the factors that hinder green buildings from achieving their fullest performance potential. Six theoretical factors namely miscommunication, technologies used, modeling tools, construction process and handover, occupant behavior and management and control were identified from various literatures. The findings in this paper will be a commencement for further studies pertaining to non-performance of green buildings. 


2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Tong Liu ◽  
Yujian Zhong ◽  
Zhihua Feng ◽  
Wei Xu ◽  
Feiting Song ◽  
...  

As a typical granular bulk medium, problems are common in boulder-cobble mixed grounds, such as easy collapse and instability and difficult effective support for large-section tunnel excavation. Tunnels constructed in BCM grounds are rare still, and there is a big gap between the design and construction of tunnels. Based on the Nianggaicun highway tunnel crossing the BCM grounds, the construction technology of tunnel in BCM grounds is studied by means of literature investigation and field survey. Here are the main conclusions: the overall deformation of surrounding rock is quite small; the pressure distribution of surrounding rock is small and loose pressure is dominant, and the safety reserve of secondary lining is large. The deformation process of surrounding rock concentrates on the construction stage. During the construction process, there are many problems, such as serious overexcavation, difficulty of bolt penetration, and continuous rock fall. In this paper, a three-bench complementary cyclic excavation method is proposed, which replaces the original CD and CRD methods. Meanwhile, the supporting system is optimized. The results show that the disturbance of surrounding rock is reduced, while the safety of construction process and the reliability of structure are increased. The new excavation method and optimized supporting system are expected to fill the gap between design and construction of tunnel in BCM grounds and provide reference for construction of such tunnels in the future.


2019 ◽  
Vol 9 (13) ◽  
pp. 2588 ◽  
Author(s):  
Jing Wang ◽  
Liping Li ◽  
Shaoshuai Shi ◽  
Shangqu Sun ◽  
Xingzhi Ba ◽  
...  

A large number of subway projects need to cross all kinds of disaster sources during the construction process. When a disaster source is unknown and uncertain, it is difficult for tunnel stability analysis to conform to the actual situation, which is likely to cause serious geological disasters. Firstly, the accurate location of the source of the disaster is realized via the geophysical method, and the orientation of the target is determined. Secondly, real imaging of the geological disaster source is realized using fine three-dimensional scanning equipment. Finally, the coupling law of the seepage field, displacement field, and stress field of the tunnel surrounding rock are analyzed. The stability of the tunnel is analyzed, and the reasonable karst treatment method is put forward.


2020 ◽  
Vol 165 ◽  
pp. 03025
Author(s):  
Jing Liu ◽  
Xiaomin Liu ◽  
Shengjie Di ◽  
Xi Lu

The large and medium-sized hydropower projects underground cavern group are basically in relatively integrate surrounding rock, so there are few engineering examples in layered surrounding rock with type III surrounding rocks as the main rock, and lack of successful experience. According to rock-bolted crane girder under the layered surrounding rock of a large underground power station, analyzing prototype dynamic monitoring data of the excavation, unloading and load-bearing test .The distribution of the monitoring data conforms to the normal law, and there are no large outliers, under the action of a large number of bolts, rock-bolted crane girder basically forms a good integrity with the layered surrounding rock, and the load-bearing test has no effect on the stress condition and stability condition of surrounding rock.


2006 ◽  
Vol 306-308 ◽  
pp. 1473-1478
Author(s):  
Wei Shen Zhu ◽  
Jian Hua Liu ◽  
Shu Cai Li

A brief description is given to the visco-plastic constitutive model of 3-D FLAC software and some treating methods for the numerical analysis. The excavation steps and the exerting time of excavation loads are determined in the light of the real construction process. The rockmass mechanical parameters are determined according to back analysis of in-situ measured displacement data. The analysis results of displacement and stability of the opening complex surrounding rocks in the construction process and in a long period of time after excavation completion are given.


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