Tunneling Method Research Articles

The use of multipotent mesenchymal cells in the complex treatment of osteonecrosis of the femoral head.

Background. Avascular necrosis of the femoral head (ANFH) is a disabling disease that often leads to hip replacement. However, due to the increasing incidence among the young population, various methods of organ-preserving treatment have been proposed aimed at slowing the progression of ANFH and preserving the function of the hip joint. Today, the procedure for introducing mesenchymal cells into the focus of osteonecrosis causes a lot of controversy and disagreement, which is the subject of discussion in our review. Aim of the study: a non-systematic analysis of the accumulated literature data on the effectiveness, safety, advantages and disadvantages of treating patients with early stages of avascular necrosis of the femoral head using the tunneling method using multipotent mesenchymal cells, as well as their impact on reducing the risk of disease progression and long-term treatment results. Material and Methods. A 10-year literature search (2013-2023) was conducted in the PubMed, Scopus and eLIBRARY databases. According to our inclusion criteria, the review included 8 high-quality studies that used mesenchymal cells to treat ANFH. Results. We analyzed 548 hips from 8 studies based on our inclusion and non-inclusion criteria. The mean follow-up period was from 24 to 360 months. In most cases, functional indicators improved. Radiological progression to the next stage occurred in 31.25% of cases and the need for hip arthroplasty was 30.6% in the group where mesenchymal cells were used. Conclusion. The use of multipotent mesenchymal cells in the complex treatment of ANFH in the early (I, II according to ARCO) stages of ANFH can improve the function of the hip joint, slow down the progression of the disease and reduce the need for hip arthroplasty.

Spatial deformation prediction method of fractured rock tunnel based on quantified GSI and its application

Determining rock mass mechanical parameters and accurately predicting tunnel deformation during tunnel construction remain challenging tasks. This study introduces a novel approach to calculate the Geological Strength Index by integrating indoor rock mechanics tests with geometric data from three-dimensional dense reconstruction. We utilized the Hoek-Brown strength criterion to develop a theoretical model for predicting tunnel deformation in fractured rock masses. Case studies reveal that the average value of Geological Strength Index for the Xiamen highway tunnel’s surrounding rock is 44. With support from the lining structure equivalent to 0.002–0.02 times the initial in-situ stress, the plastic zone thickness decreased by approximately 50%, and radial displacement was reduced by about 40%. Enhancing the lining structure’s support pressure significantly reduces the plastic zone radius and radial displacement. As the Geological Strength Index decreases, the nonlinearity between support pressure and plastic zone radius becomes more pronounced, with a similar trend observed for the relationship between support pressure and tunnel radial displacement. The relative deviation between predicted and measured values did not exceed 1.69%. The method accurately captures the effects of rock fragmentation and tunnel construction on plastic zone formation and displacement, offering an effective approach for the rapid and secure assessment of rock tunnel excavation stability using digital technology.

INOVASI PRODUKSI PACKAGING MANAJEMEN USAHA DAN DIGITAL MARKETING BERBASIS ENVIRONMENTAL SUSTAINABILITY BAGI PETANI GARAM JONO

The national need for salt increases every year along with population growth. Jono Village, Tawangharjo District, Grobogan, Central Java is known as a center for salt production. The source of the earth's spring water in the form of belik, is used by residents to make salt. Although far from the sea, the water from the source tastes salty and warm. Salt production has been around for hundreds of years. In 1960, there were hundreds of salt farmers, now there are dozens left. This requires attention from various parties. The purpose of the community service program in the Jono Village Salt Farmer Group is to provide solutions based on situational analysis of the needs, challenges, or problems that exist in the community and carry out activities that can empower the community. Specifically, with service with salt group partners, it is hoped that it can increase the production of salt, and provide more modern packaging for the salt product. This service can improve the marketing of the salt, it can be sold in modern stores, but it can only enter traditional markets. The results of the study show that Jono salt is tastier and tastier. In terms of belik water before being made into salt, the water feels warm and contains lots of minerals so it is good for health, both for skin diseases and other diseases. The method of implementing the service is carried out by conducting program socialization by the service team to Jono's salt farmer partners, with stages of training and mentoring of the service program. The training and mentoring of the program include increasing salt production with the tunnel method, packaging training using machine packaging technology, and business management mentoring and marketing mentoring. Furthermore, the application of technology in the form of a tunnel method for the salt drying process, packaging technology using a salt packaging machine, mentoring and evaluation as well as program sustainability.

Temperature field study of forced thawing by pipe curtain freezing method in Sanya submarine tunnel

Compared with other construction methods, artificial freezing technology has the advantages of good anti-penetration performance and zero pollution to the surrounding environment, and is widely used in tunnel construction under complex environment, in which the thawing temperature field during the construction period has been the focus of attention in the actual construction.Taking the freezing of the tube curtain of the undersea tunnel in the Sanya estuary waterway as the engineering background, the finite element software was used to establish a model to analyse the development of the thawing temperature field, the 0°C isotherm and the warming curves at the observation points.The results show that: when the circulating hot water temperature reaches more than 30°C, the effect of shortening the thawing time is not obvious, which means that the thawing time is gradually stabilised when the circulating hot water temperature rises to a certain value. The thawing time decreases with the increase of seepage velocity, and the effect of shortening the thawing time is not obvious when the head difference exceeds 4m, which indicates that the thawing time is gradually stabilised when the head difference increases to a certain value. The results obtained provide reference for similar projects.

6615 Clinical features and genetic etiology of primary ovarian insufficiency in 46,XX children

Abstract Disclosure: F. Wang: None. X. Yin: None. X. Lan: None. P. Li: None. Purpose: The clinical features of primary ovarian insufficiency in 46,XX children were analyzed, the pathogenic genes of POI were screened, and the genetic etiology of primary ovarian insufficiency in children 46,XX was clarified. Method: The clinical data of 46,XX POI patients were collected, including uterine and ovarian ultrasound, serum follicle-stimulating hormone (FSH), estrogen, anti-mullerian hormone (AMH), chromosomal karyotype analysis, adrenal and thyroid function, and immune function. Whole exome sequencing (WES) and CNV were used to screen POI candidate genes. Novel mutations such as MCM8 gene were used to verify cell function. HE staining, immunohistochemistry, cell fluorescence, and Tunnel method were used to observe the changes in ovarian tissue structure. Construction overexpression plasmids of Mutant MCM8 gene in Hela cells. Result: 1. Clinical features of 46,XX POI: The age of onset of the children was 11.9∼16.1 years old. In addition to POI, the clinical phenotype showed height growth retardation. Among them, 4 cases were short stature, 3 cases were growth hormone deficiency, and 5 cases were backward in bone age. All of them showed elevated FSH (>25 IU/L), and 7 cases had low serum AMH (<0.5 ng/ml). 2.The Screening of POI candidate genes and pathogenicity analysis: 5 of the 10 children carried the mutations of the pathogenic genes with POI, that is, 2 cases (sisters of the same family) carried two novel heterozygous mutations of MCM8 gene, one infant carried two novel heterozygous mutations of CYP19A1 gene, and one case with delayed puberty carried one homozygous mutation of ZSW1M7 gene. 3.The MCM8 mutant were functionally validated: The sisters carried two novel mutations, namely p.C242R and p.S445*. The elder sister (the proband) showed POI, short stature and tumor susceptibility, while the younger sister showed a trend of gradual increase in FSH level and ovarian decline. The follicles of the proband disappeared and fibrous tissue proliferation, the MCM8 expression was lower, and the positive rate of cell apoptosis was higher than normal control. The downregulation of Bax and Capase3 expression in mutant MCM8 of Hela cell was delayed compared with wild type, indicating the persistence of apoptosis. Conclusion: 1. The clinical characteristics of 46,XX POI in children are ovarian hypoplasia, often combined with height growth retardation, biochemical manifestations of hypergonadotropic hypogonadism, decreased serum AMH, and karyotype 46,XX. 2.46,XX POI genetic etiology analysis found that five known POI-related pathogenic genes, namely CYP19A1, MCM8, and ZSW1M7, in which five novel mutations were identified.3.Mutant MCM8 promotes ovarian apoptosis by activating the Bcl-2/Bax/Caspase 3 pathway. Keywords: Primary ovarian insufficiency, short stature, apoptosis Presentation: 6/3/2024

Soil Displacement of Slurry Shield Tunnelling in Sandy Pebble Soil Based on Field Monitoring and Numerical Simulation

Due to its inherent advantages, shield tunnelling has become the primary construction method for urban tunnels, such as high-speed railway and metro tunnels. However, there are numerous technical challenges to shield tunnelling in complex geological conditions. Under the disturbance induced by shield tunnelling, sandy pebble soil is highly susceptible to ground loss and disturbance, which may subsequently lead to the risk of surface collapse. In this paper, large-diameter slurry shield tunnelling in sandy pebble soil is the engineering background. A combination of field monitoring and numerical simulation is employed to analyze tunnelling parameters, surface settlement, and deep soil horizontal displacement. The patterns of ground disturbance induced by shield tunnelling in sandy pebble soil are explored. The findings reveal that slurry pressure, shield thrust, and cutterhead torque exhibit a strong correlation during shield tunnelling. In silty clay sections, surface settlement values fluctuate significantly, while in sandy pebble soil, the settlement remains relatively stable. The longitudinal horizontal displacement of deep soil is significantly greater than the transverse horizontal displacement. In order to improve the surface settlement troughs obtained by numerical simulation, a cross-anisotropic constitutive model is used to account for the anisotropy of the soil. A sensitivity analysis of the cross-anisotropy parameter α was performed, revealing that as α increases, the maximum vertical displacement of the ground surface gradually decreases, but the rate of decrease slows down and tends to level off. Conversely, as the cross-anisotropy parameter α decreases, the width of the settlement trough narrows, improving the settlement trough profile.

Requirements for partial turbulence simulations using nondimensional turbulence energy contributions

Quantifying turbulence effects is crucial for understanding building aerodynamics and for ensuring accurate wind tunnel test methods. This is especially important in wind tunnel methods that require post-experiment adjustments because approximate wind fields are used, such as the Partial Turbulence Simulation (PTS) approach. Understanding and analyzing these effects enables load adjustments since the PTS method only requires matching the high frequency portions of the upstream spectra of the longitudinal velocity component in model and full-scale. However, the limits for which the PTS method is applicable are unclear in terms of the allowable range of wind field characteristics that can be used in the wind tunnel simulation. To address this, the paper utilizes two nondimensional parameters, one representing the small-scale turbulence energy, ES, and the other the large-scale turbulence energy, EL, to elaborate the aerodynamic effects of turbulence intensity and integral length scales in the upstream wind. The results show that the maximum allowable mismatch ratio of integral length scales and of Jensen numbers between model and full-scale simulations depend on the target small-scale turbulence energy and the maximum allowable deviation of small-scale energy. By quantifying the effects of ES and EL on area-averaged pressure coefficients, the allowable limits are identified for wind tunnel test parameters that lead to negligible differences in the resultant pressure coefficient statistics in regions of separated-reattaching flow on the roof of a low-rise building.

High pre-tension reinforcing technology and design for ultra-shallow buried large-span urban tunnels

Due to the thin overlying formation of ultra-shallow buried large-span urban tunnels, the surrounding rock can be easily loosened and damaged after excavation. High prestressed anchoring support can improve the self-bearing capacity of the surrounding rock. However, traditional bolts often undergo necking fracture after the yield stage and strengthening stage, and the designed pre-tension is low, generally not exceeding 50 % of the yield strength of the bolt. To this end, our research group developed a new NPR bolt. After comparing the mechanical properties of the NPR bolt and the traditional bolt, the high strength, high elongation, and high prestressed properties of the NPR bolt are revealed. Subsequently, the constitutive relationship of the CABLE element in FLAC3D is modified, and the constitutive model of the NPR bolt is established, which can describe the whole process of bolt. Furthermore, a numerical comparison of prestressed control for ultra-shallow large-span tunnels is carried out. Compared with non-prestress, when the prestress of bolt reaches 100 kN, the area of tensile stress zone and plastic zone of surrounding rock are reduced by 79.6 % and 73.7 %, respectively. At the same time, the settlement of surface and roof is reduced by 66.7 % and 64.1 %, respectively. The control mechanism of the prestressed NPR bolt support is explored, and the design method for ultra-shallow large-span tunnels is proposed. The field application and monitoring results show that the surface and roof settlement of the tunnel supported by NPR bolts are 3.2 mm and 6.3 mm, respectively. The safe and effective stability control of the tunnel surrounding rock is achieved.

The Influence of Rock Thermal Stress on the Morphology and Expansion Pattern of the Plastic Zone in the Surrounding Rock of a Deep-Buried Tunnel under High Geothermal Temperature Conditions

The extent of the plastic zone is critical in determining the stability and extent of damage to the surrounding rock in tunnels, crucial for designing support structures and thermal insulation layers. This study focuses on understanding how rock thermal stress affects the expansion of the plastic zone in deep-buried tunnels subjected to high geothermal temperatures, based on the derivation of the boundary line formula of the plastic zone in a high geothermal tunnel, and combined with the test results of the hydraulic fracturing method in a high geothermal tunnel of the Bulunkou Hydropower Station in Xinjiang. The findings indicate that thermal stress in the rock mass slows the growth of the plastic zone but significantly increases its extent. However, the influence of thermal stress on the shape and size of the plastic zone is less significant compared to the lateral pressure coefficient. In conditions of high geothermal temperature and geostress, rock mass thermal stress induces substantial changes in the morphology and extent of the plastic zone, which cannot be overlooked and can lead to significant errors if not properly considered. The theoretical formulas derived from engineering analysis, along with observed patterns of plastic zone expansion, demonstrate practical applicability.

Continuous Slag Discharge Construction Technology for Shield Tunneling in Narrow Space Environment

The shield tunneling method is the main construction method in subway tunnel construction, which has the characteristics of safety, efficiency, mechanization, and high degree of automation. However, the shield tunneling equipment is huge, the supporting facilities are numerous, and the site requirements are high. In response to the problems of slow slag removal speed and low construction efficiency in shield tunneling under the construction conditions of small wellhead shield tunneling sections in urban subways, taking the shield tunneling section of Guangzhou Metro Line 13 Phase II as the background,This article introduces the main components, working principles, installation and transportation processes, fault handling, and benefit analysis of the continuous belt conveyor slag removal system,This article elaborates on the method of using a continuous belt conveyor in the tunnel combined with a vertical lifting system at the wellhead to achieve continuous slag removal during underground shield tunneling construction in a narrow wellhead construction site. This not only improves excavation efficiency but also reduces construction costs, solves construction problems, and provides reference for similar projects in the future.

Improved Subsidence Assessment for More Reliable Excavation Activity in Tehran

This paper presents a particular tunneling method, the new Austrian tunneling method (NATM), which plays an important role in reducing subsidence of the surface and damage to structures in urban areas. It has a wide range of applications in shallow tunneling projects all over the world. In this study, numerical modeling of the third-line Metro tunnel in Tehran, which is designed and stabilized by the NATM, is under discussion. The foregoing tunnel is excavated manually with a one-meter advancing step. In this project, the constructors use a lattice girder and spray concrete with 31 cm thickness as the initial lining. A suitable numerical software for this modeling is PLAXIS 3D Tunnel, which allows high-resolution finite element modeling (FEM) of the studied object. The performance of this method is investigated and compared with that of other NATMs. The numerical modeling yielded a value of 30.01 mm for earth subsidence in the most damaged area of the settlement, which was confirmed with a dramatically low difference by earth surface monitoring. Moreover, this tunnel was drilled and excavated using various methods, among which the least settlement was obtained by the proposed method. The results are promising, and they indicate that tunneling with this method should continue to be used to expand the subway line in the city.

Inverse design of bistable composite laminates with switching tunneling method for global optimization

Bistability enables adaptive designs with tunable deflections for applications including morphing wings, robotic grippers, and consumer products. Composite laminates may be designed to exhibit bistability due to pre-strains that develop during the processing of the polymer matrix, enabling fast reconfiguration between two stable shapes. Unfortunately, designing bistable laminates is challenging because of their highly nonlinear behavior. Here, we propose the Switching Tunneling Method to address this challenge by alternating between gradient-based local minimization and tunneling search phases, with the enhancement of objective expression switching to improve numerical conditioning. Results demonstrate high effectiveness compared to existing optimizers; the Switching Tunneling Method achieves a 99% success rate in finding all energy minima across general composite layups. Additionally, our method facilitates the inverse design of variable pre-strain fields, enabling bioinspired, positive Gaussian curvatures, which are not possible with conventional pre-strain laminates. Validations through both finite element analysis and 3D printed samples confirm the optimal designs.

Reconfigurable directional selective tunneling of p-type phonons in polarized elastic wave systems

There have been many studies on the ground state of phononic crystals, but few studies on the nature of the excited state. In this paper, we introduce the asymmetric Klein tunneling method in phononic systems, which enables selective direction and control of elastic waves by inducing polarization through an external field in an artificial barrier. Using tight-binding theory, we systematically studied phononics in a super-honeycomb structure, demonstrating the anisotropic transition properties of excited state phonons through a matrix model involving the ground state’s s-type and the first excited state’s p-type wave functions. Additionally, we exploit the thermal sensitivity of epoxy to achieve localized thermal field-induced distortion of the bottom flat band, forming a tiled Dirac cone, and thereby creating a reconfigurable polarized artificial barrier in the elastic wave system. Elastic waves propagate in these systems with topological charge conservation. Combining this with the theoretical of excited-state phonons, we demonstrate asymmetric Klein tunneling with directional selectivity in the elastic wave carriers, and systematically investigate the performance of this tunneling. Furthermore, we design a four-port elastic waveguide based on the principle of asymmetric tunneling, which achieves exceptional directional selectivity of elastic wave signals by adjusting the polarization direction of barriers at the junctions. These studies not only extend the application of Klein tunneling in elastic wave systems but also open new research avenues for the study of elastic wave devices controlled by various external fields, showing direct application potential in elastic wave signal processing.

Safety evaluation method for operational shield tunnels based on semi-supervised learning and a stacking algorithm

The safety assessment of structural defects in operational shield tunnels is crucial for ensuring their serviceability and safe operation. This study developed a novel comprehensive evaluation method for tunnel safety assessment based on semi-supervised learning and a stacking ensemble algorithm. First, in the membership degree calculation of the multidimensional normal cloud model, the importance coefficients of the tunnel safety evaluation indicators were used instead of their weights to improve the cloud model. This allowed generating unlabeled samples with patterns consistent with those of the collected samples with structural defects. Three classifiers, namely, random forest, extra trees, and gradient boosting, were employed for semi-supervised learning. This process converted unlabeled samples into pseudo-labeled samples, expanded the structural defects database, and ultimately optimized the classifier performance. Subsequently, a stacking algorithm was used to integrate the three optimized classifiers. This resulted in the creation of three stacking models, each containing multiple metamodels. Finally, the optimal metamodels were selected based on accuracy, precision, recall, and F1 score for a voting scheme to determine the tunnel safety level. The developed evaluation method was applied to a real-world engineering project. The evaluation results demonstrated consistency with those obtained from actual field conditions, thus validating the reliability and rationality of the proposed method.

Wind loading on gable and multi-span roof buildings: Comparison between field monitoring, wind tunnel experiments, and design code provisions

The wind loading provisions in the National Building Code of Canada (NBCC) have not been updated for decades despite developments in wind tunnel methods since the original source data. This study aims to review the Nbcc 2020 provisions compared to wind tunnel experiments, field measurements, and the ASCE 7–22 provisions for single and multi-span gable roof buildings. Field measurements and wind tunnel tests are used to collect data for an isolated building and later for a multi-span gable. The pressure coefficients from the field measurements were mostly higher than the wind tunnel, which is consistent with previous studies. The results provided evidence that NBCC provisions for single-gabled roofs (with slope 7∘<α≤27∘) and multi-span gabled roofs (with slope 10∘<α≤30∘) are currently underestimated. New provisions are suggested for the corner (c), edge (s), and field (r) zones of the single-span gabled roof and for gable-end-edge (s’) zone of the multi-span. It is suggested to merge Zone s into Zone c to form a new perimeter Zone p for the single gabled roof and to merge Zone s’ into Zone c for the multi-span gabled roof. The proposed changes correct the current provision underestimation and add simplicity for easier construction.

An overview of potential excavation compensation method for tunnelling in deep rock engineering

The complicated geological environment of deep rocks poses new challenges to tunnel and mining engineering. Some thorny disasters such as large deformation of soft rock and rockburst are becoming more and more prominent. However, the classic tunnelling methods represented by the mine tunnelling method and the new Austrian tunnelling method are generally unsatisfactory in addressing these issues due to the limited self-stability of surrounding rock mass. Therefore, the excavation compensation method (ECM) with the core of active stress compensation has been proposed and applied in practical engineering construction to solve the above problems. After extensive engineering practice, the theoretical foundation, key technologies, and construction system of ECM have been established and improved. This article provides a comprehensive overview of this novel tunnelling method. In addition, its controlling effects on surrounding rock are demonstrated by two typical engineering examples. It could provide some new ideas and references for the development of future tunnelling technology.

An optimized observation system and inversion method for fault detection based on surface-wave while tunneling

Understanding geological structures ahead of the tunnel face is important for safe and efficient construction of the urban tunnel. The surface-wave while tunneling (SWT) method, using drilling noise by shield machine as source, is expected to dynamically predict the adverse geologies in front of the tunnel face. Observation system and inversion method are keys for SWT. To improve the imaging accuracy of the geological conditions, it is urgent to optimize the observation system for data acquisition and inversion method for velocity inversion, especially for the utilization of multi-modes surface-waves. For observation system, several key parameters (minimum source-geophone distance, length and interval of survey line) are optimized to obtain sufficient information of dispersion curves. Then observation systems for source at different depth were optimized, supporting for geological detection using surface-waves generated by underground drilling noise. For velocity imaging, numerical simulations are studied to reveal the applicability of typical inversion methods for multi-modes of surface wave, and particle swarm optimization (PSO) algorithm is optimized for velocity inversion due to its advantages of stable calculation and good accuracy. On this basis, SWT was optimized both in data acquisition and velocity inversion for better understanding geological condition both in buried depth and detection distance. Then the improved method was applied in the Jinan tunnel and successfully detected a fault, providing geological information for construction safety and verifying the feasibility.

Comparison of femoral tunnel position and knee function in anterior cruciate ligament reconstruction: a retrospective cohort study using measuring-fluoroscopy method versus bony marker method

BackgroundPrevious studies have shown that surgical technique errors especially the wrong bone tunnel position are the primary reason for the failure of anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to compare the femoral tunnel position and impact on knee function during the ACL reconstruction using measuring combined with fluoroscopy method and bony marker method for femoral tunnel localization.MethodsA retrospective cohort study of patients undergoing ACL reconstruction using the bony marker method or measuring combined with fluoroscopy for femoral tunnel localization was conducted between January 2015 and January 2020. A second arthroscopic exploration was performed more than 1 year after surgery. Data regarding patient demographics, the femoral tunnel position, results of the Lysholm score, the International Knee Documentation Committee (IKDC) score, KT-1000 side-to-side difference, pivot shift grade, and Lachman grade of the knee were collected.ResultsA total of 119 patients were included in the final cohort. Of these, 42 cases were in the traditional method group, and 77 cases were in the measuring method group. The good tunnel position rate was 26.2% in the traditional method group and 81.8% in the measuring method group (p < 0.001). At the final follow-up, the Lysholm and IKDC scores were significantly greater in the measuring method group than the traditional method group (IKDC: 84.9 ± 8.4 vs. 79.6 ± 6.4, p = 0.0005; Lysholm: 88.8 ± 6.4 vs. 81.6 ± 6.4, p < 0.001). Lachman and pivot shift grades were significantly greater in the measuring method group (p = 0.01, p = 0008). The results of KT-1000 side-to-side differences were significantly better in the measuring method group compared with those in the traditional method group (p < 0.001).ConclusionsThe combination of the measuring method and intraoperative fluoroscopy resulted in a concentrated tunnel position on the femoral side, a high rate of functional success, improved knee stability, and a low risk of tunnel deviation. This approach is particularly suitable for surgeons new to ACL reconstructive surgery.

Engineering geological and geotechnical evaluation of Sathya Sai Prasanthi Nilayam railway tunnel, Andhra Pradesh, India

Detailed engineering geological investigations were carried out for a railway tunnel which was constructed more than two decades ago. 3D engineering geological mapping was carried out using Brunton Compass and Total Station Surveying instruments in 1:100 scale. Coarse-grained pink and grey granite, hornblende-biotite gneiss and dolerite dyke of Archaean age and Lower Proterozoic age were mapped. Rock mass was intersected by sub-horizontal, inclined, and vertical joint sets, which were continuous and persistent, smooth, and planar with thick filling of decomposed and crushed sheared material or with thin coating of clay material. Based on the Q-system, rock mass was classified into different classes. On the basis of large-scale engineering geological mapping and Norwegian Method of Tunnelling, a support system was recommended which includes rock bolt, fibre reinforced shotcrete, grouting and reinforced ribs of sprayed concrete and the same is implemented by the agency. As per the best knowledge of the authors, reinforced ribs of sprayed concrete are first time used for transportation tunnels in India and it will be more effective if it will be compared with ISMB or Lattice Girder.

Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field