Tunneling Method Research Articles

Predicting advance rate and cutter life in TBM tunnelling using evolutionary algorithm

ABSTRACT Tunnelling with a Tunnel Boring Machine (TBM) offers several advantages over conventional tunnelling methods when covering long distances, particularly regarding time, safety, and environmental impact. Prior to starting a TBM project, performance analysis is a crucial stage necessary to inform the initial investment decision and project cost estimation. However, this analysis requires extensive fieldwork and laboratory studies. The Advance Rate (AR), calculated from the Utilization Factor (U) – the ratio of excavation time to total project time – is a widely accepted measure of TBM performance. Total project time encompasses various parameters, including boring time, cutter inspection and replacement times, and constant factors like re-gripping, service, and maintenance times. In this study, we employed analytical methods, statistical analysis, and genetic programming approaches to evaluate the AR and thus enhance TBM performance analysis. Gamma tests were conducted to identify interrelated parameters in TBM operations. The results from these tests showed that the Applied Force per Cutter (FN) and penetration values (together forming the Field Penetration Index or FPI) are useful in estimating cutter consumption. While FN can be determined through laboratory tests, its field determination is challenging. We have developed several charts and a function derived from genetic programming to estimate the AR of a TBM. The study demonstrated that this function, formulated using genetic programming, possesses strong predictive capability and can significantly improve TBM performance analysis.

Research on Excavation Method for Soft Rock Tunnel Based on Stress Release Rate

A test method for controlling the stress release rate of the tunnel by adjusting the confining pressure is proposed based on the engineering background of Dongmachang No. 1 Tunnel of Huali Expressway to explore a suitable excavation method of soft rock tunnel. Based on the relationship between stress release rate, displacement release rate, and longitudinal advance of excavation face, the model test of tunnel excavation is carried out. On this basis, combined with the horizontal loading test and field monitoring results, the influence of three excavation methods, the three-bench method, three-bench with reserved core soil method, and three-bench seven-step method, on the mechanical behavior of the tunnel is studied. The research shows that the load shared by the double-layer initial support is not equal, and the second-layer initial support only bears 20% of the pressure of the first-layer initial support; replacing the three-bench method with the three-bench core soil method and the three-bench seven-step method can reduce the deformation of the surrounding rock by 8.7~12.4%, and the load borne by the supporting structure is transferred from the second layer to the first layer. In order to take into account the safety and efficiency of tunnel construction, it is recommended to use the three-bench core soil method for excavation. The research results can provide a theoretical reference for the construction of related tunnel projects.

Solving Conformal Mapping Issues in Tunnel Engineering

The calculation of conformal mapping for irregular domains is a crucial step in deriving analytical and semi-analytical solutions for irregularly shaped tunnels in rock masses using complex theory. The optimization methods, iteration methods, and the extended Melentiev’s method have been developed and adopted to calculate the conformal mapping function in tunnel engineering. According to the strict definition and theorems of conformal mapping, it is proven that these three methods only map boundaries and do not guarantee the mapping’s conformal properties due to inherent limitations. Notably, there are other challenges in applying conformal mapping to tunnel engineering. To tackle these issues, a practical procedure is proposed for the conformal mapping of common tunnels in rock masses. The procedure is based on the extended SC transformation formulas and corresponding numerical methods. The discretization codes for polygonal, multi-arc, smooth curve, and mixed boundaries are programmed and embedded into the procedure, catering to both simply and multiply connected domains. Six cases of conformal mapping for typical tunnel cross sections, including rectangular tunnels, multi-arc tunnels, horseshoe-shaped tunnels, and symmetric and asymmetric multiple tunnels at depth, are performed and illustrated. Furthermore, this article also illustrates the use of the conformal mapping method for shallow tunnels, which aligns with the symmetry principle of conformal mapping. Finally, the discussion highlights the use of an explicit power function as an approximation method for symmetric tunnels, outlining its key points.

Sequential Human Histology Results of the Subperiosteal Minimally Invasive Aesthetic Ridge Augmentation Technique (SMART): A Chronologic Wound Healing Proof-of-Principle Study.

Traditional GBR procedures have been associated with frequent complications and compromised peri-implant esthetics. Tunneling techniques have been proposed as a promising alternative in this regard. More recently, a subperiosteal minimally invasive aesthetic ridge augmentation technique (SMART) was reported to have been clinically successful in a prospective case series. This technique includes the use of a bone graft/recombinant human platelet-derived growth factor-BB combination delivered to the site by a tunneling method. However, published histologic information regarding the nature of the regenerated tissue has been limited. The current study evaluated the histologic and histomorphometric findings of four human specimens harvested at 2, 5, 9, and 14 months after ridge augmentation using the SMART method. Evaluations of the wound healing and bone regeneration sequence over time found that the ridge augmentation was the result of extensive new bone formation that progressed through the woven bone to lamellar bone stages, with remodeling of the xenogeneic graft material and replacement by patient bone. This is the first study utilizing sequential human specimens to histologically examine the chronology of wound healing following alveolar ridge augmentation.

Insights into the role of the H-abstraction reaction kinetics of amines in understanding their degeneration fates under atmospheric and combustion conditions.

Amines, a class of prototypical volatile organic compounds, have garnered considerable interest within the context of atmospheric and combustion chemistry due to their substantial contributions to the formation of hazardous pollutants in the atmosphere. In the current energy landscape, the implementation of carbon-neutral energy and strategic initiatives leads to generation of new amine sources that cannot be overlooked in terms of the emission scale. To reduce the emission level of amines from their sources and mitigate their impact on the formation of harmful substances, a comprehensive understanding of the fundamental reaction kinetics during the degeneration process of amines is imperative. This perspective article first presents an overview of both traditional amine sources and emerging amine sources within the context of carbon peaking and carbon neutrality and then highlights the importance of H-abstraction reactions in understanding the atmospheric and combustion chemistry of amines from the perspective of reaction kinetics. Subsequently, the current experimental and theoretical techniques for investigating the H-abstraction reactions of amines are introduced, and a concise summary of research endeavors made in this field over the past few decades is provided. In order to provide accurate kinetic parameters of the H-abstraction reactions of amines, advanced kinetic calculations are performed using the multi-path canonical variational theory combined with the small-curvature tunneling and specific-reaction parameter methods. By comparing with the literature data, current kinetic calculations are comprehensively evaluated, and these validated data are valuable for the development of the reaction mechanism of amines.

Wearable Clothing Drop Box Design Using Persuasive Design Approach

The phenomenon of fast fashion (the trend of dressing in a short period of just six months to two years) is a trend that occurs today. This trend raises the problem of stacking clothes. Clothes that are not reused should be used and distributed to others in need or known as the recycling concept. This study aims to design a drop box that can collect and distribute suitable clothes by using Persuasive Design approach. Dropbox is used to improve the concept of sustainability of clothing products. The initial stage of the study was an interview to explore the target of user behaviour in using clothes and explore the inhibiting factors experienced by users due to confusion in distributing their used clothes. Affective design approach is chosen by applying tunnelling, reduction and conditioning technology methods. Dropbox design built in a physical and digital display of the product. The product evaluation process using Usability Testing with the results obtained an efficiency rate of 100%, an effectiveness of 90.625%, and a System Usability Score (SUS) of 83.44, showing that the prototype has good usability. In the persuasive aspect, namely effectiveness, quality, and capability, average values of 5.75, 6.125, and 5.958 were obtained. Improvement recommendations are made based on the results of evaluation by respondents, namely make a clear information at drop box product and display improvement.

Less invasive bonnet bypass with subcutaneous tunneling method for common carotid artery occlusion - A technical note.

Common carotid artery occlusion (CCAO) sometimes requires vascular reconstruction. Ipsilateral superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is unsuitable due to insufficient blood flow to the external carotid artery. The bonnet bypass, one treatment option for CCAO, requires a long coronal incision and bone groove to prevent malposition and collapse of an interposition graft. However, this long incision might lead to skin complications and reduced collateral blood flow. A 60-year-old man who experienced recurrent ischemic stroke presented with the right internal carotid artery occlusion and left CCAO. The left STA was unavailable; however, both branches of his right STA were well-developed. Minimizing skin invasion was a priority because the patient had diabetes mellitus. We performed a right STA parietal branch - right MCA anastomosis, followed by a right STA frontal branch - left radial artery graft (RAG) - left MCA bonnet bypass using small intermittent skin incisions. We drilled a bone groove extending across the entire length of the interposition graft through the small intermittent skin incisions. Furthermore, we applied a right STA-RAG end-to-side anastomosis instead of an endto-end anastomosis to preserve collateral skin anastomosis. Postoperatively, the bypass remained patent, and the patient was discharged without complications. The bonnet bypass is a potential treatment for CCAO, but the procedure is invasive. Our modified bonnet bypass method enables less invasive management, preventing collapse and malposition of the interposition graft and minimizing skin complications.

A simplified sclerocorneal tunnel approach in performing pediatric cataract surgery.

Performing pediatric lensectomy, anterior vitrectomy with intraocular lens implantation in one session, using a long sclerocorneal tunnel and covering the incision site with 8/0 Vicryl sutures. This study includes 52 eyes of 30 patients with pediatric cataracts. At the temporal side, the conjunctival peritomy was performed, followed by two long sclerocorneal side ports and the main incision for intraocular lens (IOLs) implantation. At the end of the operation, the side port and the conjunctiva incisions were sutured with 8/0 Vicryl sutures. The IOLs were implanted in children older than 24 months, not in smaller ones. The operations and intraoperative complications were recorded. After the operation, the patients were examined on the 1st postoperative day, then six times for the first 6 months. During follow-ups, the impact of the suture on the anterior segment complications and astigmatism was evaluated. The age of the patients ranged between 2 months and 8 years. The average operation time was 28 ± 6 min. Due to the suture-related complication, neither re-suturing nor stitch removal was carried out; therefore, general anesthesia was not repeated. The average astigmatism value of the children in the postoperative 1st week was 1.5 ± 1.2 D (0.5-4.0). The mean astigmatism value was 0.8 ± 0.5 D (0.5-1.5) in the 3rd postoperative month. The long corneoscleral tunnel method has been found safe in pediatric cataract surgery.

Construction and Evaluation of The Wind Tunnel Technique for Estimating Ammonia Volatilization from Land

Agriculture is mainly responsible for ammonia (NH3) volatilization. Among all agricultural activities, livestock and especially animal manures are the most important sources of NH3 emissions. Manure application which not only exacerbate greenhouse gas emissions, but also leads to eutrophication of water bodies. Many studies have shown that surface application of manure can lead to large ammonia losses and run off, on the other hand that tillage can substantially reduce these losses. It is necessary to determine ammonia flux from manure-amended soils to improve management manure handling practices for minimizing agriculture’s impact on the environment. From this point of view, one of the direct measured method was used to determine this volatilization. The objections of this work were: i) The design, construction, physical calibration, and operation of the little wind tunnels. ii) Recover ammonia loss from bovine slurry by little wind tunnel method. iii) Determine the effect of slurry application depth on ammonia emission. The little wind tunnel system consisted of plastic canopy covering the treatment area (2 m long by 0.5 m wide). By was using a fan, it was imitated the natural wind speed in the test area (1-1.5 m/s). Nitrogen losses were measured with this method in surface application, 50 mm and 100 mm subsurface. In the surface application, the highest ammonia emission was observed. It was approximately 68% higher in compared to another methods. There is significantly (P=0.05) different in the ammonia emission, between the surface apply method and injection manure in soil methods. But There isn’t any significantly different between ammonia emission amount in injection subsurface methods (100 mm and 50 mm deep).

Cavity behind Special Segment Structures in Upward Shield Tunneling: A Numerical Approach

Proper design of special segments under cavity conditions is essential for successfully implementing the upward shield tunneling method. When constructing upward tunnels, the segment structure in the corresponding construction area of the horizontal tunnel is special. To study the internal force distribution on the structure under the worst possible conditions given by the upward shield tunneling method, MIDAS GTS NX software is used to numerically simulate the structure based on the condition of the cavity behind it to determine the most unfavorable radius of the cavity. Moreover, an analysis of the cavity location is conducted. The results demonstrate that when the cavity is located at the bottom of the arch with a radius of 1 m and near the top of the arch with a radius of 0.5 m, the special segment structure is under the most unfavorable combination of stresses. The most dangerous working condition occurs when there is a 0.5 m radius cavity on one side of the arch in the cross‐section of the special segment.

Flood Mitigation Management Practice: A Comparison Between Stormwater Management Road Tunnel (SMART) and Sponge City Methods

Flash flood in Malaysia urban is no longer a surprise incident as it has become a widespread natural disaster that frequently happened every year. The geographical of Malaysia with equatorial climate experiences consistently high temperatures with high relative humidity and influenced by the northeast and southwest monsoons have provided heavy rainfall during the monsoon season. Although the flood issue has been given an important focus under the disaster management implementation in Malaysia, there is critical demand to improve the present flood mitigation management practice to overcome unforeseen flood disaster issues over the long term. The annual occurrence of floods in Malaysia has caused a very big impacts to the lives of humans and other living beings that requires serious attention and better “solution alternative” measures in urban areas. Commentators have remarked that the current urban flood management method, i.e., Stormwater Management and Road Tunnel (SMART) has not been proven as the long-term best solution to overcome the unforeseen flood disaster issues over the long term. There have been suggestions from the scholars to explore and adopt a new method, i.e., Sponge City concept that is still scarce in Malaysia but has been substantially adopted in China to overcome the urban flood issues. Therefore, this paper is prepared to present the outcome of the study on the comparison between the present Stormwater Management and Road Tunnel (SMART) and the newly concept of Sponge City with specific reference to the urban flood mitigation management in Malaysia. This study employs a quantitative research strategy to collect primary data from fifty-eight (58) respondents that approximately represents 73% of the entire distributed questionnaires or a total of 80 potential respondents that was identified to meet the specified criteria, with the objective to get their opinions on the comparison between the two competing methods, i.e., the present SMART tunnel, and the newly Sponge City concept for urban flood mitigation management in Malaysia. The findings revealed that the majority of the respondents chose Sponge City because it is greater advantages than the SMART tunnel method to overcome the issues of flood disaster in the urban areas. Although the Sponge City concept could be deemed appropriate for consideration as the new and better flood mitigation management method in Malaysia, it demands a holistic assessment to view the relevancy of Sponge City implementation and its investment over the life span for achieving economic sustainability and Sustainable Development Goals (SDGs).

Bayesian updating for ground surface settlements of shield tunneling

Accurate prediction of ground surface settlements induced by shield construction is of great significance for ensuring the safety of shield construction. This paper proposes a ground surface settlement prediction method for shield tunneling based on Bayesian updating. The sequential observation data during the advance of excavation is utilized to update the key soil parameters, leading to a more accurate settlement prediction for the subsequent excavation stages. Response surfaces are constructed to replace the finite element model as the forward models for higher computational efficiency. A tunnel excavation project in Hangzhou, China, is selected to illustrate the effectiveness of the proposed method. The shield excavation face passes through four soil layers, and two soil parameters (i.e., Young’s modulus and friction angle) of these soil layers are selected as random variables to be updated. The results show that the soil parameters can be effectively updated based on the observation data at multiple points and various excavation stages. The predictions of ground surface settlements are improved by using the updated soil parameters. The prediction accuracy of the proposed method increases as more stages of observation data are sequentially obtained and incorporated.

Stochastic Simulation of Construction Methods for Multi-purpose Utility Tunnels

The traditional method of installing underground utilities (e.g., water, sewer, gas pipes, electrical cables) by burying them under roads has been used for decades. However, the repeated excavations related to this method cause problems, such as traffic congestion and business disruption, which can significantly increase financial and social costs. Multi-purpose Utility Tunnels (MUTs) are a good alternative for buried utilities. Although the initial cost of MUTs is higher than that of the traditional method, social cost savings make them more feasible, especially in dense urban areas. Different factors, such as the specifications of utilities, the location of the MUTs, and the construction method, should be investigated to determine if MUTs can be an economical and practical alternative. The construction method is one of the most important factors to assess to have a successful MUT project and reduce its impact on the surrounding area. Simulation can be used to investigate the different construction methods of MUTs. In this paper, two Stochastic Discrete Event Simulation models depicting two MUT construction methods (i.e., microtunneling and cut-and-cover) are developed to analyze the duration and cost of the MUT projects. Also, 4D simulation models of these methods are developed for constructability assessment of these projects.

A Rock Mass Classification Method for Tuff Tunnel Based on the High-Pressure Gas Expansion Method

A precise rock mass grade result is crucial for directing the tunnel excavation engineering design. A novel rock mass classification method for tuff tunnel based on the high-pressure gas expansion method (HPGEM) was proposed, which was primarily built on field test data previously acquired by the research team. The main achievements are as follows: combined with field data and the HPGEM rock-breaking theory, analyzing the rock uniaxial compressive strength, rock mass integrity index, and the relationship between the gas generator unit consumption and fitted the relevant equations. After that, the rock optimal uniaxial compressive strength (about 150 MPa) and the rock integrity factor (about 0.85) were obtained. With reference to the BQ rock mass classification method, a new rock mass classification method that applied to HPGEM was proposed. This study fills the gap of the appropriate rock mass classification method requested on HPGEM.

Single-port intragastric wedge resection using the tunnel method: a novel surgical approach for treating endophytic gastric subepithelial tumors.

Intragastric wedge resection is an effective method for treating endophytic gastric subepithelial tumors (SETs). However, retracting the stomach wall to the umbilicus is difficult in certain patients. In response, we developed a novel surgical technique for single-port intragastric wedge resection, which we termed the "tunnel method." A transumbilical incision is made, and a wound retractor is applied. After diagnostic laparoscopy, a gastrostomy is made on the greater curvature, lower body. Another small wound retractor is inserted into the gastrostomy, and extracted through the transumbilical incision, creating a tunnel from the gastrostomy site to the umbilicus. Articulating laparoscopic instruments are inserted via the tunnel, and intragastric wedge resection is performed. We collected and analyzed the clinicopathologic and operative data of patients who underwent intragastric wedge resection via the tunnel method. Twenty-seven patients who underwent single-port intragastric wedge resection via the tunnel method in a single tertiary referral hospital were included in this study. The mean age of the patients was 54.6 ± 11.4years, body mass index was 26.5 ± 3.4kg/m2. Twenty-four (88.9%) patients had tumors located in the upper third of the stomach. The average operative time was 65.0 ± 24.2min. None of the patients experienced Clavien-Dindo grade IIIa or higher postoperative complications. The average postoperative hospital stay length was 2.5 ± 0.8days. Thirteen gastrointestinal stromal tumors, nine leiomyomas, and one neuroendocrine carcinoma, schwannoma, lipoma, spindle cell proliferative lesion, and fibrotic lesion were pathologically diagnosed. The average tumor size was 2.6 ± 1.3cm. All cases had negative resection margins. Single-port intragastric wedge resection by the tunnel method is a feasible and safe approach for treating endophytic gastric SETs.

A Theoretical Study on the Resilience Evaluation Method of Operational Road Tunnel Systems

Road tunnel operation will suffer from a lot of uncertain external disturbances, which will greatly affect the operational safety of road tunnels and even block traffic. Focusing on road tunnel operation safety and disaster-resistant ability, the concept of resilience is introduced to provide a scientific and effective basis for road tunnel operation and emergency management. In this paper, the concept of tunnel system resilience was proposed based on the concept of system resilience. A theoretical analysis model of road tunnel resilience was built to describe the change in road tunnel system function over time due to external disturbances (e.g., fires, traffic accidents, floods, earthquakes). Five fundamental attributes of road tunnel system resilience were proposed to describe the resilience level. A resilience evaluation method for road tunnels was proposed based on the functional network. The vulnerable links of road tunnels subjected to external disturbances can be analyzed using this method. This study will provide important references for the resilience evaluation method of road tunnels and risk mitigation strategies.

Expanding the Scene of Tunnel Behaviour Through the DEM Model: a Case Study from ZaB-Zentrum Am Berg

The displacement of a tunnel plays a crucial role in conventional tunneling methods, serving as a key parameter for support requirement. Therefore, analyzing tunnel displacement is important for ensuring safety and optimizing costs by determining the appropriate level of tunnel support and installation time. Numerical analysis methods are commonly employed for assessing tunnel displacement, and two widely recognized approaches used worldwide are the continuum and discontinuum methods. While previous studies have highlighted differences in the analysis results obtained from these two methods, the magnitude of such disparities has not been extensively explored. Hence, the objective of this study is to quantify the extent of variation between the two methods through various scenarios, encompassing unsupported and supported excavated ground. Specifically, the focus is on tunnel displacement and the tensile force generated on axial tunnel supports, such as rock bolts. To facilitate this investigation, three tunnel sections from the Zentrum am Berg, tunnel research centre located in Austria, are utilized. The results show that discontinuum models exhibit higher displacements and higher tensile loads on axial support than continuum numerical models of the same tunnel geometry and equivalent rock masses. We show that discontinuum models can also capture asymmetric behaviour, and thus should be preferentially used in fractured rock masses where displacement of rock blocks dominate the rock mass behaviour.

A high-precision positioning method for shield tunneling based on dual-axis hybrid inertial navigation system

During shield tunneling excavation, it is extremely important to obtain the accurate positions of the control points which determines the quality of the tunnel construction. The present process of measuring and checking the control points is labor-intensive and time-consuming. In this paper, we proposed a high-precision positioning method using a dual-axis hybrid inertial navigation system (HINS) mounted on a rail transport vehicle to measure the positions of control points automatically without other external sensors. Considering the movement constraints on the rails, an improved non-holonomic constraints (NHC) algorithm was introduced to promote navigation accuracy and a new calibration method of mounting angle errors was proposed. The semi-physics experiment and laboratory rail experiments were conducted whose results showed that the lateral position accuracy was increased by more than 94.23% and the vertical position error was reduced to the centimeter level averagely using the proposed algorithm compared to the normal INS algorithm.

Theoretical Kinetic Study on Hydrogen Abstraction Reactions from n-Pentane by NO2.

The interaction of fuel with NOx chemistry is important for the construction of the reaction mechanism and engine application. In this work, the reaction pathways of nC5H12 + NO2 were studied by high-level electronic structure calculations (DLPNO-CCSD(T)-F12/cc-pVTZ-F12//B2PLYPD3/cc-pVTZ). The rate constants were calculated by using the multistructural canonical transition-state theory with the Eckart tunneling method (TST/MS-T/ET). The studied condition is in a wide temperature range of 298-2400 K. The influence of MS-T anharmonicity and tunneling effect will be clarified for these site-specific H-abstraction pathways. The result reflects the large deviation introduced by the treatment of MS-T anharmonicity, especially at a high temperature. For the same type of reactions, the rate constants of H-abstraction both occurring at the secondary carbon are not almost identical. The branching ratios show that abstraction from the secondary site forming cis-HONO (R2c) contributes 36-78% to nC5H12 consumption in the temperature range of 298-2400 K. The current results show that the multistructural torsional anharmonicity has a crucial influence on the accurate estimation of branching ratios.

Stress analysis of elliptical tunnels in an orthogonally anisotropic elastic full‐space under non‐uniform in‐situ stress

AbstractNon‐uniformly distributed in‐situ stress around the tunnel is a significant factor inducing various geohazards during tunnel excavation in the rock mass, and the anisotropy of the rock mass would further differentiate the in‐situ stress state around the tunnel. To ensure the safety of tunnel construction and operation, it is necessary to deeply analyze the stress distribution law and mechanical mechanism of the orthogonally anisotropic elastic media the around tunnel. This paper presents a complex variable function method for the elliptical tunnel in an orthogonally anisotropic elastic full‐space under non‐uniform in‐situ stress. To obtain the analytical solution, the affine transform and conformal mapping are applied to consider the orthogonal anisotropy of material and the ellipticity of the tunnel. A numerical series fitting method is introduced to describe the non‐uniformly distributed load, and then the stress solution around tunnel is further obtained. The comparisons with the existing literature, numerical solutions and model tests are provided to verify the correctness of the proposed method. Finally, the convergence study and the numerical analysis on the stress distribution are given graphically.