scholarly journals Muck Problems in Subway Shield Tunneling in Sandy Cobble Stratum

2016 ◽  
Vol 23 (s1) ◽  
pp. 175-179 ◽  
Author(s):  
Kai Cui ◽  
Weikang Lin
Keyword(s):  
Control Method ◽  
Low Cost ◽  
Earth Pressure ◽  
Reference Value ◽  
Field Application ◽  
Geological Condition ◽  
Construction Technology ◽  
Shield Tunneling ◽  
Shield Machine ◽  
Epb Shield

Abstract Experiments aiming at the muck improvement for Chengdu’s subway shield tunneling in water-rich sandy cobble ground initially finds out the kinds and ratio of muck improver suitable for the this strata, and through the field application determines the reasonable ratio of muck improver for shield tunneling in sandy cobble ground, providing a reference to other muck improvement for shied tunneling in similar ground. And the earth pressure balanced shield is widely used in tunnel engineering, with its characteristics as wide adaptability, safe operation, fast driving speed, low environmental noise and low cost. Taking Chengdu Metro Line as the background, aiming at the difficulty faced by EPB shield tunneling in water-rich sandy cobble ground, and based on the explorations and researches of the predecessors and scholars, engineering and technical personnel, the present paper combines with engineering examples to make a systematic summary and research on key construction technology of EPB shield tunneling through sandy cobble ground from the aspects of EPB shield adaptability, , structure and transformation of cutter and helical unearthed wares, settlement control method, and muck improvement measures. It has certain reference value and guiding significance to the selection of shield machine and the reconstruction of shield machine in complex geological condition.

Coordinated optimization control of shield machine based on dynamic fuzzy neural network direct inverse control

2020 ◽  
pp. 014233122098027
Author(s):  
Xuanyu Liu ◽  
Wentao Wang ◽  
Yudong Wang ◽  
Cheng Shao ◽  
Qiumei Cong
Keyword(s):  
Fuzzy Neural Network ◽  
Control Method ◽  
Earth Pressure ◽  
Screw Conveyor ◽  
Inverse Control ◽  
The Earth ◽  
Coordinated Optimization ◽  
Optimization Control ◽  
Fuzzy Neural ◽  
Shield Machine

During shield machine tunneling, the earth pressure in the sealed cabin must be kept balanced to ensure construction safety. As there is a strong nonlinear coupling relationship among the tunneling parameters, it is difficult to control the balance between the amount of soil entered and the amount discharged in the sealed cabin. So, the control effect of excavation face stability is poor. For this purpose, a coordinated optimization control method of shield machine based on dynamic fuzzy neural network (D-FNN) direct inverse control is proposed. The cutter head torque, advance speed, thrust, screw conveyor speed and earth pressure difference in the sealed cabin are selected as inputs, and the D-FNN control model of the control parameters is established, whose output are screw conveyor speed and advance speed at the next moment. The error reduction rate method is introduced to trim and identify the network structure to optimize the control model. On this basis, an optimal control system for earth pressure balance (EPB) of shield machine is established based on the direct inverse control method. The simulation results show that the method can optimize the control parameters coordinately according to the changes of the construction environment, effectively reduce the earth pressure fluctuations during shield tunneling, and can better control the stability of the excavation surface.

Delivering More Fit-for-Purpose Wells with Low Cost Approach at Untapped Area Matured Field – Application of Cone Concept Statistical Approach

2021 ◽  
Author(s):  
M. Hatta M. Yusof ◽  
M. Zarkashi Sulaiman ◽  
Rahimah A. Halim ◽  
Nurfaridah Ahmad Fauzi ◽  
Ahgheelan Sella Thurai ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Statistical Approach ◽  
Control Method ◽  
Low Cost ◽  
Volatile Oil ◽  
Field Application ◽  
Well Design ◽  
Execution Phase ◽  
Sand Control ◽  
Fit For Purpose

Abstract This paper discusses the Case study of Field A in offshore Sarawak, Malaysia which focus on re-thinking development based on statistical analysis of the fields. Conventionally, well design is driven by subsurface requirement by targeting the high-reserve sand and well is designed to meet subsurface objectives. However, the conventional way may not be efficient to develop matured field environment due to the high CAPEX and the inconsistencies among well design especially in current volatile oil price period. The objective of this fit-for-purpose approach which is called "Cone Concept Statistical Approach" is to steer away from the conventional way of targeting only sweet spots whilst leaving the remaining potential resources undeveloped. Based on the statistical analysis and subsurface fields pattern, the "Cone Concept Statistical Approach" in which standardizing well design and trajectories was developed to extract the whole fields’ reserve at maximum. Well design boundaries were introduced to ensure this approach can be replicated throughout the field. Not only this study covers drilling perspective, completion perspective was also taken into consideration by exploring a cheaper and fit for purpose sand control method, considering it is a matured field with relatively short remaining field life. The Well Cost Catalogue for this field-specific approach was also developed which contains different types of design and completion, in order to holistically evaluate sand control method and identify the best option for the project moving forward. This "Cone Concept Statistical Approach" aims to enable operator to drill simple wells within the same allocated budget in which poses low-to-no risk in the design and execution phase. This promotes a learning curve to improve operation & HSE, and ultimately gets positive project economics. Since this simple approach can be implemented early on even during the pre-FEL stage, the FDP team & host authority can come together to jointly discuss the targets/platform ranking and segregate them into various phases. Hence, the number of platforms or drilling centers, and its location also can be optimized early on with this concept, and again, translating into further reduction in overall project cost. This paper will help other operators and host authority to understand better on how a specific development concept on statistical approach can result and turn the matured-challenging fields into more economically attractive projects – low overall development cost and maximizing the recovery.

Research on Chamber Earth Pressure of EPB Shield Considering Soil Arching Effect

2014 ◽  
Vol 1065-1069 ◽  
pp. 373-377
Author(s):  
Jing Cao ◽  
Hai Xing Yang ◽  
Bo Liang ◽  
Hai Ming Liu
Keyword(s):  
Earth Pressure ◽  
Shield Tunnel ◽  
Pressure Balance ◽  
Soil Arching ◽  
Shield Tunneling ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Earth Pressure Balance ◽  
Tunnel Depth ◽  
Epb Shield

Chamber earth pressure is one of the significant parameters during the Earth Pressure Balance (EPB) shield construction processing. The soil arching effect is existence when the tunnel depth is enough. It is significant to consider the influence of arching effect to analyze the pressure in soil chamber in shield tunneling. In this paper, the influence of arching effect is considered to calculate the chamber earth pressure. Firstly, the soil is supposed as loose media, and the necessary buried depth of producing arching affects is deduced according to the loose media theory. Then, based on the characteristic of proper arching axis, the equation and the height of proper arch are obtained. At last, the calculation formula of minimum chamber earth pressure of EPB shield tunnel is deduced which can consider the effect of arching effect.

Control Parameters of EPB Shield Tunneling in Weathered Granite Ground and Below Existing Tunnels

2011 ◽  
Vol 243-249 ◽  
pp. 3572-3581
Author(s):  
Xing Gao Li ◽  
Da Jun Yuan ◽  
Hao Hu
Keyword(s):  
Collaborative Work ◽  
Earth Pressure ◽  
Measured Data ◽  
Second Phase ◽  
Control Parameters ◽  
Shield Tunneling ◽  
Weathered Granite ◽  
The Earth ◽  
Epb Shield ◽  
Advance Speed

The choice of reasonable parameters of EPB shield tunneling in weathered granite ground is of great importance to reduce tunneling-induced effects on existing tunnels. Combined with the practice of the EPB shield tunneling below existing interval tunnels from Kexueguan station to Dajuyuan station of Shenzhen metro line No.1, the method of design and regulation of main parameters including the earth pressure in excavation chamber, the ground conditioning, the volume of the discharged soil, the grouting control and the advance speed, of the EPB shield tunneling are studied. The practice of the below-crossing shows in the weathered granite ground, it is reasonable that the earth pressure in excavation chamber is taken as 0.15-0.2 mpa, and that FER, FIR and CF of foam are taken as 8-15, 30-50% and 3-5% respectively, and that the amount of synchronization grouting is 8-10 m3 per ring along with the injecting pressure of 0.3-0.4 mpa, and that the second phase injection is employed to control the further settlement of existing tunnels when necessary, and that the advance speed is taken as 8-10 mm/min, and as steady as possible. Meanwhile, adjustments according measured data must be performed when necessary. Moreover, the real-time monitoring and a collaborative-work environment among the Parties involved in project are also very crucial to facilitate the risk management of the below-crossing.

scholarly journals A Data-Driven Method for Predicting the Cutterhead Torque of EPB Shield Machine

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kairong Hong ◽  
Fengyuan Li ◽  
Zhenjian Zhou ◽  
Feng Li ◽  
Xunlin Zhu
Keyword(s):  
Linear Regression ◽  
Short Term Memory ◽  
Thrust Force ◽  
Change Point Detection ◽  
Linear Regression Method ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
Start Up ◽  
Shield Machine ◽  
Epb Shield

The prediction of cutterhead torque of earth pressure balance (EPB) shield machine is mainly studied. First, the idea of shield tunneling stage division is proposed. The process of shield tunneling from start to stop (or pause) is divided into start-up and stationary driving stages. Using the change point detection method based on linear regression, the separation points between start-up stage and stationary driving stage are identified from the original construction data, and the datasets of the two stages are extracted, respectively. Then, for the start-up stage, the linear regression method is suggested for the cutterhead torque prediction, since there is a strong linear correlation between the key parameters such as the cutterhead torque and the thrust force. Meanwhile, for the stationary driving stage, considering the fact that the key parameters vary smoothly and show obvious inertia, the long short-term memory (LSTM) network method can be used to establish the relationship model between cutterhead torque and other key parameters, such as the thrust force. Through the test experiments of construction data in Zhengzhou, Luoyang, and Dalian shield projects, the results show that the proposed segmented modeling method possesses good adaptability and the cutterhead torque prediction model has high prediction accuracy.

scholarly journals Experimental Study on the Soil Conditioning Materials for EPB Shield Tunneling in Silty Sand

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Chi-Hao Cheng ◽  
Shao-Ming Liao ◽  
Xiao-Bo Huo ◽  
Li-Sheng Chen
Keyword(s):  
Earth Pressure ◽  
Test System ◽  
Cutting Performance ◽  
Silty Sand ◽  
Test Results ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
Soil Conditioning ◽  
Sand Stratum ◽  
Epb Shield

Earth pressure balance (EPB) shield tunneling in a silty sand stratum is frequently faced with the wear of rotary cutter disc, clogging, or even collapse of workface due to its noncohesive and discrete properties of silty sand material. Soil conditioning is an effective way to reduce the discrete and friction properties of silty sand and to increase its rheology and fluidity, thus improving the cutting performance of EPB machines. However, soil conditioning materials were generally prepared and injected based on past limited field experiences or lab tests which were far from reality. In this article, a ground suitability test system for simulating shield tunneling in a conditioned ground was specially developed and used in a series of tests to investigate the influences of key factors of soil conditioning on the shield cutting performance. In addition, a field experiment of shield tunneling in silty sand of Wuhan Metro was conducted for verification. The major findings were obtained as follows. (1) The proposed test system performed well in simulating and assessing the cutting performance of EPB shield in conditioned soils, and the test results agreed well with the field test. (2) The soil conditioning materials can significantly reduce the cutting torque of shield tunneling in silty sand by up to 60%–70%. (3) The optimal foam and slurry parameters are suggested in the paper for shield tunneling in silty sand, respectively. (4) The test results reveal that the slurry conditioning is better than the foam in decreasing the cutter torque in silty sand. To achieve the same effect of soil conditioning, the injection ratios of foam and slurry should be 45% and 10%, respectively, to achieve the torque reduction ratio of 60%. These findings can provide a practical reference for engineers to determine the best-fit conditioning materials and construction parameters in the silty sand stratum.

Effect of Shield Tunneling on the Nearby Pile Foundations

2011 ◽  
Vol 250-253 ◽  
pp. 3559-3563
Author(s):  
Ya Jun Wu ◽  
Dao Min Zou ◽  
Gang Li
Keyword(s):  
Concrete Strength ◽  
Reference Value ◽  
Negative Influence ◽  
Pile Foundations ◽  
Shield Tunneling ◽  
Pile Shaft ◽  
Practical Engineering ◽  
Shield Machine ◽  
Two Sides ◽  
Tunnel Shield

Shield tunneling may have negative influence on the nearby facilities. Especially, it will cause the additional stresses and moments along the pile shaft. If the stresses and deformation of a pile exceed the allowable values, that will affect its normal use and even result in its damage. Therefore, base on a practical engineering in Shanghai, some factors such as the distances between a pile and a tunnel, the concrete strength of a pile are investigated using finite diffrence method. The results show: the degree of disturbing soil in two sides of the tunnel is greater than that of soil in front of the tunnel; shield tunneling has a strong effect on a pile within a distance of 3m between the pile and the shield machine; however, if the distance is in excess of 3m, the effect is not too strong. Furthermore, the grade concrete strength of a pile has little effect on the pile behavior. This conclusion has some reference value to the actual project.

Online Fault Prediction for EPB Shield Tunneling Based on Neural Network

2012 ◽  
Vol 457-458 ◽  
pp. 1287-1293 ◽  
Author(s):  
Bu Hai Shi ◽  
Wei Qing Li
Keyword(s):  
Neural Network ◽  
Earth Pressure ◽  
Risk Process ◽  
Fault Prediction ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
The Neural Network ◽  
Earth Pressure Balance ◽  
Artificial Neural Network Ann ◽  
Epb Shield

For the complex earth conditions and uncertain factors, the earth pressure balance (EPB) shield tunneling is a complicated and high-risk process. There would cause some faults, such as earth caking, soil occluding in the capsule, water spewing, surface settlement. To avoid them, this paper applies artificial neural network (ANN) to predict the common shielding faults. The neural network is trained by several samples about the tunnel boring machine’s (TBM) parameters, and then it will have self-learning to identify the fault. With the parallel computing ability, the network could detect and predict abnormal behaviors online. This paper includes three parts, firstly, the introduction of EPB, and four usual blockings; and then the principle of BP neural network is present, for the defect of BP algorithm, two kinds of improved BP algorithms are applied in the network; finally, an simulation is given to illustrate the prediction.

scholarly journals Experimental Study of the Influence of Excavation Surface Stability and Sand Flowability Caused by Dense Slurry–Earth Pressure Balance Shield Tunneling in Silty Sand Stratum

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yongjin Qian ◽  
Fanlu Min ◽  
Zhenze Mo ◽  
Xihui Fan
Keyword(s):  
Pore Pressure ◽  
Filter Cake ◽  
Earth Pressure ◽  
Rate Of Change ◽  
Silty Sand ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
Earth Pressure Balance ◽  
Sand Stratum ◽  
Epb Shield

Silty sand is highly permeable and has a large internal friction angle. To ensure the stable and efficient construction of the Earth pressure balance (EPB) shield in silt stratum, it is necessary to reduce the disturbance to the stratum during tunneling and reduce the risk of spewing and blocking during soil discharge. Thus, a new type of dense slurry-EPB shield construction technology is proposed. Using a custom-made test device, the consolidation tests were conducted on sand after mixing it with different amounts of slurry to study the change in the pore pressure in the mixed soil and sand stratum and analyze the stress transmission rule. In addition, slump tests were conducted on the mixed soil to study the change in the fluidity. Based on the laboratory test results, a field investigation was carried out to study the effects of the amount of slurry addition on the pore pressure in the stratum, the driving parameters, and the sand’s flowability during shield tunneling. The results show that when the amount of slurry reaches a certain value, the filter cake effect occurs. The greater the amount of slurry added during the shield tunneling, the smaller the rate of change of the pore pressure in the stratum. When the amount of BC2 slurry added reached 8 m3 per ring, the rate of change was reduced by 57%, and the slump value improved by 93%. The type of filter cake of the DS-EPB shield was only internal filter cake during tunneling, which reduced the disturbance of the excavation face and improved the flowability of the sand. These results are of great significance to the application and promotion of DS-EPB shields in sandy cobble strata.

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