Tunnel Volume Research Articles

Numerical Modeling of Soil and Structure Behavior for Tunneling in Different Types of Soil

This note studies the correlation between surface and tunnel volume loss in various types of dry soil via finite element method. The effect of small strain stiffness, the buoyancy effect of soil, and tunnel overburden depth are considered in the 2D tunneling model. The results show that both surface volume loss ratio and settlement trough width parameter in the empirical solution can be expressed as a linear equation of tunnel volume loss ratio for 1D overburden shallow tunnels. Furthermore, the surface volume loss ratio can be presented as a non-linear polynomial equation of overburden depth and tunnel volume loss ratio in a 3D space, and this equation holds in different types of soil. The ranges of required fitting parameters and upper and lower bounding surfaces are suggested for various types of soil. Knowledge of this correlation between surface and tunnel volume loss is valuable, as it can be employed in practice for preliminary tunnel design in the absence of tunneling induced maximum ground settlement.

Resorption characteristics of an open architecture biocomposite interference screw after ACL reconstruction.

Absorbable interference screws for anterior cruciate ligament reconstruction (ACLR) can lead to tunnel widening and cyst formation. The Biosure Regenesorb interference screw (Smith & Nephew). has been developed with an optimised calcium phosphate/polymer composition to promote bone formation during resorption. The present study aims to investigate screw resorption, new bone formation, and tunnel geometry following ACLR with Biosure Regenesorb screw tibial fixation. The study is a prospective single-centre case series of 12 patients with ACL lesions and treated with ACLR using hamstring tendon autograft with Biosure Regenesorb interference screw tibial fixation with a two-year follow-up period. The Biosure Regenesorb consists of 65% polylactide-glycolic acid poly. 20% calcium sulphate and 15% tricalcium phosphate. Primary endpoint: Tunnel volume. implant volume and new bone formation in the tibial tunnel is evaluated by quantitative computed tomography (CT) scanning. Secondary endpoints: Arthrometric knee laxity, International Knee Documentation Committee (IKDC) and Knee Osteoarthritis and Injury Outcome Scores (KOOS) and Tegner activity scale. Screw volume decreased to 44% within the two-year follow-up period while tunnel volume remained unchanged. Only a minor amount (<1% of tunnel volume) of new bone formation in the screw remnants was observed. Sagittal knee laxity at one year was 0.9 mm. The IKDC score increased by 15 points and the KOOS sport and KOOS quality of life scores increased by 25 and 26 points. respectively. ACLR using Biosure Regenesorb interference screw does not result in tunnel widening. showing a screw resorption of 44% after two years and minor new bone formation. Knee stability and subjective outcome improvements are as expected after other ACLR methods. IV.

Radiographic Tibial Tunnel Assessment After Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts and Biocomposite Screws: A Prospective Study With 10-Year Follow-up.

Biocomposite screws reportedly provide equivalent graft fixation in anterior cruciate ligament reconstruction (ACLR) to metallic screws while simplifying subsequent imaging and surgery. One purported complication of biocomposite screws is paradoxical tunnel widening. Previous studies on beta-tricalcium phosphate screws have only reported outcomes at short- and midterm follow-up. To radiographically assess the tibial tunnel 10 years after ACLR using hamstring tendon autografts and biocomposite interference screws in anatomic single-bundle (SB) and double-bundle (DB) methods. Case series; Level of evidence, 4. Of the 105 initially recruited patients, 61 (58%) completed all follow-up evaluations for inclusion in this long-term study. A total of 26 patients received anatomic SB ACLR and 35 patients received DB ACLR with biocomposite interference screws containing beta-tricalcium phosphate in the tibia. Weightbearing anteroposterior and lateral radiographs of the index knee were taken in the early postoperative period and at 2, 5, and 10 years postoperatively; computed tomography (CT) imaging was performed at 10-year follow-up. Subjective and objective clinical assessments were recorded preoperatively and at 10-year follow-up. The mean follow-up period was 122 months. In 76% of radiographs in the SB group, the width of the tibial tunnel had not increased at 10 years compared with the early postoperative period. The mean tibial tunnel volume on CT in the SB group was 2.04 cm3 (± 0.85 cm3). In the DB group, the posterolateral tunnel width had not increased in 69% of radiographs; the same was found in 63% of radiographs for the anteromedial tunnel at 10-year follow-up. The mean posterolateral tunnel volume on CT was 2.04 cm3 (±1.92 cm3) and the mean anteromedial tunnel volume was 1.38 cm3 (±0.54 cm3). There was no correlation between tunnel widths and KT-1000 arthrometer assessments. There was a moderate but statistically significant correlation between SB tibial tunnel volume on CT imaging and KT-1000 arthrometer anterior 134 N side-to-side difference (r = 0.45; P = .039). Most patients' tibial tunnels had not increased on 1 or both radiographic views at 10-year follow-up compared with the early postoperative period after ACLR using biocomposite interference screws, with no obvious negative effect on outcomes. However, the tunnels were still visible in most patients at 10 years on standard radiographs and CT imaging.

In-tunnel pollutant concentration measurement and ventilation control indexes for highway tunnels in mountainous area: A case study of no.1 Qinling tunnel, China

The pollutant concentration and hygiene standards in mountain tunnels are key factors determining the ventilation effectiveness of tunnel operation. Previous studies have mainly focused on the spatiotemporal distribution patterns of in-tunnel pollutants, while research on ventilation control indexes for pollutants in long mountain tunnels are relatively limited. Therefore, this paper aims to discussing the hygiene control indexes for operational ventilation of mountain tunnels. Field tests were conducted in the No.1 Qinling Tunnel of Xi'an to Han zhong Highway in China, and the distribution laws of traffic flow, wind speed, and concentrations of particulate matter (PM), carbon monoxide (CO), and nitrogen oxide (NOX) were on-site measured. The spatiotemporal distribution characteristics of pollutants in the long mountain tunnel were revealed, and the ventilation hygiene control indexes for harmful gases were calculated and compared to those of urban highway tunnels. The results show that the traffic volume of operational highway tunnels in mountainous areas of China is increasing rapidly, and the particulate matter emitted from diesel vehicle exhaust will pose a threat to the normal environmental quality in the tunnel. The average value of CO base emission factor in 2000 for the upline of No.1 Qinling tunnel was 0.0019 m3/(veh·km) by back-calculation, and the annual decline rate of CO in the ventilation design for mountain highway tunnels should be 6 %–8 % and revised every 8 years. It is recommended to consider the geographical location and traffic conditions of mountain tunnels when calculating the air demand required for diluting NO2. NOx has basically replaced CO as the primary pollutant with the most significant impact on human health in mountain tunnels. It is recommended that NOX be considered as the primary hygiene control indicator in the ventilation design of mountain tunnels in China. The pollutant distribution and ventilation control indexes of mountain and urban highway tunnels are quite different, which should be treated differently in engineering applications. The research results can provide a significant reference for ventilation design and environmental evaluation of highway tunnels in mountainous areas.

Morphometric indices and carpal tunnel syndrome: aradiological study in female patients.

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy syndrome of the upper extremities. The carpal tunnel is an osteofibrous canal that is medially bordered by hamulus ossis hamati and pisiform bone, and laterally by scaphoid and trapezoid bones. In this retrospective case-control study, we investigated the relationship between radiologically measured morphometric indices and CTS in female patients. Clinical, radiological, and demographic data were collected for 55 hands of 40 female patients diagnosed with CTS and 58 hands of control subjects. Radiological measurements included various morphometric parameters derived from wrist and hand X-rays. Statistical analysis was conducted to assess associations between morphometric indices and CTS. Significant associations were observed between CTS and several morphometric indices, including carpal height, capitate length, palm length, and others. Notably, these values were lower in CTS patients, suggesting a potential link between reduced carpal tunnel volume and increased pressure due to synovial hypertrophy. Additionally, a newly introduced index, Scaphoid Pisiform Width Index (SPWI), showed promise in assessing the proximal part of the carpal tunnel. It was found that the values for Capitate length, Carpal height, Palm length, SPWI, and Palmar ratio were lower in the patient group. These results suggested that decreasing volume of the carpal tunnel allows for an easier increase in carpal tunnel pressure due to increased synovial hypertrophy and the carpal bone configuration affects the proximal part of the carpal tunnel, and influences the compression of the median nerve, in female patients.

Tunnelling-induced nonlinear responses of continuous pipelines resting on tensionless Winkler foundation

Prevailing analytical approaches for tunnelling-induced soil-pipeline interactions predominantly rely on linear analyses, limiting their applicability in nonlinear scenarios. This study introduces a novel tensionless Winkler solution that accounts for gap formation and soil yielding, validated against three well-documented experiments and demonstrating superiority over existing Winkler solutions. Additionally, plate load tests refine traditional soil-bearing theories for buried pipelines in sand, providing subgrade stiffness and ultimate bearing capacity values pertinent to tunnelling-induced interactions. Parametric studies highlight amplified nonlinearity in pipeline behaviours with increased pipeline flexural rigidity and tunnel volume loss, due to soil-pipeline separation and subgrade yielding. Notably, ignoring gap formation and soil yielding leads to overly conservative estimations of pipeline deflections and bending moments. Higher subgrade moduli increase pipeline strains, while enhanced subgrade bearing capacity above the pipeline prevents soil yielding, rendering its effect negligible, whereas the bearing capacity beneath the pipeline is inconsequential in tunnelling scenarios.

Morphological characteristics of the cubital tunnel as indication for anterior interosseous nerve supercharge end-to-side transfer in treating advanced cubital tunnel syndrome

BackgroundCubital tunnel syndrome (CuTS) is a prevalent compressive neuropathy addressed through various treatments, including the anterior interosseous nerve (AIN) supercharge end-to-side (SETS) transfer for advanced CuTS. Decision to add AIN-SETS is based on various indicators and protocols, but deciding on the appropriate method for borderline cases can be challenging. Therefore, this study aims to non-invasively examine the cubital tunnel anatomy of patients using CT scans and compare the findings with existing indicators and measurements, to determine if they can serve as supplementary indicators to aid in treatment decisions. HypothesisThe bony cubital tunnel volume is correlated to other traditional indicators and can be used as an additional indication for deciding whether to perform AIN-SETS in treating advanced CuTS. Patients and MethodsThis is a single-center retrospective cohort study from South Korea, including 91 patients aged 20–70 years with CuTS. Participants were classified into Group A (n = 43), who underwent both cubital tunnel release (CuTR) and AIN-SETS, and Group B (n = 48), who underwent only CuTR. Preoperative elbow CT data were analyzed for cubital tunnel morphology analysis, with follow-up assessments such as grip strength and electromyography/ nerve conduction velocity (EMG/NCV) tests at 3, 6, and 12 months postoperatively. ResultsGroup A and B showed no significant differences in demographic parameters, except for a longer disease duration in Group A (p = 0.032). Group A had a smaller cubital tunnel volume (CTV) compared to Group B (1150.6 ± 52.8 mm3 vs. 1173.5 ± 56.2 mm3, p = 0.014) and a smaller cross-sectional area (40.9 ± 10.2 mm2 vs. 45.1 ± 11.7 mm2, p = 0.033). Pearson correlation analysis revealed statistically significant positive correlations between CTV measurements and pre-operative grip strength, as well as EMG results, a key indicator for AIN-SETS (R2 = 0.48, 0.23, p = 0.01). DiscussionMeasuring the cubital tunnel anatomy using CT can aid in determining the treatment approach for advanced CuTS patients and assist in deciding whether to perform AIN-SETS surgery, serving as a supplementary indicator for cases at the borderline limits of other indicators. Future research may be necessary to establish control groups without symptoms and determine appropriate cut-off values. Level of evidenceIV.

Improvement of thermostability by increasing rigidity in the finger regions and flexibility in the catalytic pocket area of Pseudoalteromonas porphyrae κ-carrageenase.

Poor thermostability reduces the industrial application value of κ-carrageenase. In this study, the PoPMuSiC algorithm combined with site-directed mutagenesis was applied to improve the thermostability of the alkaline κ-carrageenase from Pseudoalteromonas porphyrae. The mutant E154A with improved thermal stability was successfully obtained using this strategy after screening seven rationally designed mutants. Compared with the wild-type κ-carrageenase (WT), E154A improved the activity by 29.4% and the residual activity by 51.6% after treatment at 50°C for 30min. The melting temperature (Tm) values determined by circular dichroism were 66.4°C and 64.6°C for E154A and WT, respectively. Molecular dynamics simulation analysis of κ-carrageenase showed that the flexibility decreased within the finger regions (including F1, F2, F3, F5 and F6) and the flexibility improved in the catalytic pocket area of the mutant E154A. The catalytic tunnel dynamic simulation analysis revealed that E154A led to enlarged catalytic tunnel volume and increased rigidity of the enzyme-substrate complex. The increasing rigidity within the finger regions and more flexible catalytic pocket of P. porphyrae κ-carrageenase might be a significant factor for improvement of the thermostability of the mutant κ-carrageenase E154A. The proposed rational design strategy could be applied to improve the enzyme kinetic stability of other industrial enzymes. Moreover, the hydrolysates of κ-carrageenan digested by the mutant E154A demonstrated increased scavenging activities against hydroxyl (OH) radicals and 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radicals compared with the undigested κ-carrageenan.

Rational optimization of substituted α‐MnO2 cathode for aqueous zinc‐ion battery

AbstractDensity functional theory (DFT) is utilized to explore the effects of increasing concentrations of vanadium (V) and chromium (Cr) substitution on the discharge of α‐MnO2 cathode in hydrated zinc‐ion batteries (ZIBs). During H+‐intercalation and Zn2+‐intercalation, Cr‐substitution proves to be more effective than V‐substitution in promoting discharge behaviors. Transitioning from Mn0.875Cr0.125O2, Mn0.75Cr0.25O2 to Mn0.625Cr0.375O2 is found to consistently enhance the discharge voltage, along with improved tunnel structure retention and volume expansion suppression. In comparison, the promoting effect of increasing V‐substitution is relatively small at initial discharge stages and leads to degradation at later stages, primarily due to an increased concentration of unstable Mn2+ ion. The superior effect of Cr‐substitution is attributed to the unique atomic and electronic structures of substituted Cr4+ and reduced Cr3+ ions during discharge. These ions serve as active electron acceptors to limit the formation of Mn3+ and Mn2+ ions, and as anchors to stabilize the α‐MnO2 framework and intercalated H+/Zn2+ ions, respectively. Our study highlights fine‐tuning through substitution to enhance the performance of α‐MnO2‐based cathode materials in ZIBs.

Health Risk Prediction of Operational Subsea Tunnel Structure Based on Bayesian Network

Recently, subsea tunnel construction has developed rapidly in China. The traffic volume of subsea metro tunnels is large. Once a safety accident occurs, economic losses and social impacts will be extremely serious. To eliminate accidents in operational subsea metro tunnel structures, a health risk prediction method is proposed based on a discrete Bayesian network. Detecting and monitoring data of the tunnel structures in operation were used to evaluate the health risk by employing the proposed method. This method establishes a Bayesian network model for the health risk prediction of the shield tunnel structure through the dependency relationship between the health risk of the operational tunnel structure and 13 risk factors in five aspects: the mechanical condition, material performance, integrity state, environmental state, and deformation state. By utilizing actual detection and monitoring data of various risk factors for the health risk of the operational subsea metro shield tunnel structure, this method reflects the actual state of the tunnel structure and improves the accuracy of health risk predictions. The validity of the proposed method is verified through expert knowledge and the subsea shield tunnel structure of the Dalian Subway Line 5. The results demonstrate that the health risk prediction outcomes effectively reflect the actual service state of the shield tunnel structure, thus providing decision support for the control of health risks in the subsea metro shield tunnel.

Presoaking Grafts in Vancomycin Does Not Impair Graft-Bone Healing in a Rat Anterior Cruciate Ligament Reconstruction Model

Background: The vancomycin presoaking technique (wherein grafts are treated with a vancomycin solution [VS] for anterior cruciate ligament reconstruction [ACLR]) reduces the infection rate after ACLR. However, the effects of this technique on graft-bone healing have not been fully elucidated. Purpose: To investigate the effects of vancomycin presoaking on graft-bone healing in a rat ACLR model. Study Design: Controlled laboratory study. Methods: Long flexor digitorum longus tendons were obtained from 9 Wistar rats, and each was randomly allocated to the normal saline (NS) or VS groups. The grafts were immersed in sterile saline for 30 minutes in the NS group and in a 5-mg/mL VS in the VS group. The presence of time-zero graft bacterial contamination was confirmed, and the grafts were incubated in Fluidised Thioglycollate Broth for 2 weeks. ACLR was performed on the right knees of 65 male Wistar rats using the flexor digitorum longus tendons. Each graft was similarly treated. Biomechanical testing, micro–computed tomography, and histological evaluations were performed 4 and 12 weeks postoperatively. Results: The VS group showed significantly reduced graft contamination at time zero (P = .02). The mean maximum loads to failure were 13.7 ± 8.2 N and 11.6 ± 4.8 N in the NS and VS groups, respectively, at 4 weeks (P = .95); and 23.2 ± 13.2 N and 30.4 ± 18.0 N in the NS and VS groups, respectively, at 12 weeks (P = .35). Regarding micro–computed tomography, the mean bone tunnel volumes were 3.76 ± 0.48 mm3 and 4.40 ± 0.58 mm3 in the NS and VS groups, respectively, at 4 weeks (P = .41); and 3.51 ± 0.38 mm3 and 3.67 ± 0.35 mm3 in the NS and VS groups, respectively, at 12 weeks (P = .54). Histological semiquantitative examination revealed no clear between-group differences at any time point. Conclusion: Presoaking grafts in vancomycin in a rat ACLR model demonstrated no discernible adverse effects on short- and midterm biomechanical, radiological, and histological investigations. Clinical Relevance: The findings provide guidance for surgeons when considering this technique.

Assessment of Building Response Supported on Shallow Foundation Due to Tunnelling in Cohesionless Soil

The depth of foundations significantly influences the building response due to tunnelling-induced ground movement. The present study investigates the responses caused by tunnelling on buildings supported on isolated footings. The response of buildings supported on shallow foundation systems due to progressive tunnelling is investigated through experimental and numerical methods. A three-dimensional finite element analysis (3D FEM) has been developed to evaluate the response of an existing reinforced cement concrete (RCC) building underpasses a circular-shaped tunnel in cohesionless soil. The model includes soil strata, footings, super-structure, and tunnel. Different parametric studies, i.e., C/D ratios, tunnel volume losses, and eccentricity of the building, have been considered in the present study. A scale-down model of the tunnel and building is prepared in the laboratory. The scale-down model simulates the volume loss during tunnelling and evaluates the response on surface and building components due to tunnelling. The surface settlement, total and differential settlement of the foundation, and induced strain on lining and building elementals are estimated. The numerical model is benchmarked with the experimental study conducted in the laboratory. It is observed that the numerical method agrees well with the experimental investigation. The responses of buildings supported on shallow footings are compared with available literature. The findings of the present study will be useful for the hazard estimation of existing buildings situated along/adjacent to a proposed alignment of the tunnel.

Load transfer mechanisms for capped and uncapped non-displacement piles above tunnels: a centrifuge modelling study

This paper presents results from geotechnical centrifuge tests of tunnelling in dry dense sand beneath loaded non-displacement piles, focusing on the effect of a pile cap (representative also of a raft or grade beam) in contact with the soil surface on load transfer mechanisms. Experiments included loading tests to ascertain the foundation capacity and load-displacement response in the presence/absence of an underlying model tunnel. Individual ‘reference’ pile response is compared for cases with and without a pile cap, including pile displacements and load distributions between the head, shaft, and base; the case of ‘friction’ piles with a compressible base are also considered. Results show that uncapped piles with relatively large service loads experience ‘geotechnical failure’ (i.e. large settlements or a significant increase in settlement rate with tunnel volume loss) in order to mobilise base or shaft resistance. Pile caps are shown to reduce settlements and prevent geotechnical failure of both reference and friction piles; they also improve the post-tunnelling foundation performance under loading. The paper provides evidence to enable engineers to consider the beneficial role of shallow elements in contact with the surface on the performance of pile foundations both during and subsequent to tunnelling.

Using a biomimetic sonar bat robot to explore the sensory world of bats in the field and in the laboratory

Bat species such as those belonging to the families of horseshoe and Old World leaf-nosed bats make their navigation decisions based on echoes that are often received from dense vegetation. To gain an understanding of how these animals accomplish navigation based on such complicated clutter echoes, a biomimetic sonar system that replicates the auditory periphery of bats has been used as synthetic observer to probe the sensory stimulus ensemble of the bats in a flight tunnel as well as in the field. Both laboratory and field experiments were carried out in Brunei on the island of Borneo. For the flight tunnel, the biomimetic sonar robot has been used to record a large number of pulse and echo pairs in conjunction with an array consisting of 28 ultrasonic microphones. In this experiment, the sonar head was positioned at points spaced on a 3d grid that covers the tunnel's volume. This data set will be used to train a deep neural network to predict the inputs to the ears of a bat maneuvering in the tunnel. In the field experiments, the sonar head was carried off road in various tropical-forest habitats to record echo samples in conjunction with precise GPS location references.

Design, Validation and CFD Modeling of an Environmental Wind Tunnel

The wind erosion of granular materials stored within the open yards of industrial plants (i.e., industrial wind erosion) and the subsequent emission and dispersion of particulate matter (PM) in the surrounding areas represent an important issue for the exposed population and for the environment as a whole. The Environment Impact Assessment (EIA) and the design of emission control measures require a deep knowledge of the erosion phenomenon, and the precise estimation of the Emission Factors (EF) associated with the specific PM source under investigation. Aiming to characterize the emission potential of industrial granular materials, a new Environmental Wind Tunnel (EWT) has recently been built at the Department of Civil and Environmental Engineering and Architecture (DICAAR) laboratories, in Cagliari University. The article discusses the EWT’s updated design and the set-up methodologies applied to reproduce the Atmospheric Boundary Layer (ABL) acting over the surfaces of coarse and heterogeneous granular materials. In addition, a Computational Fluid Dynamics (CFD) model of the EWT has been developed to reproduce and analyze the wind field throughout the entire tunnel volume and preliminarily evaluate possible modifications to the original design. The accuracy of the simulation has been verified by comparing the CFD model and the results of the experimental tests.

Experimental evidence that increased surface temperature affects bioturbation by ants.

Ants are important bioturbators that actively produce biopores and move soil particles. They could be particularly affected by global warming as they are ectotherms. Nevertheless, they can indirectly regulate their temperature, through changes in their circadian cycles and the architecture of their nests (e.g. digging deep nests or using insulating materials). Nest architecture has been considered an expanded functional trait of ant colonies and thus sensitive to environmental changes such as increasing temperatures. This work aimed to study the nest architecture of ants as a functional trait and its effects on soil bioturbation. We hypothesized that, when exposed to increased surface temperatures, ants would increase their excavation activities, build deeper nests and alter the layout of chambers to maintain their preferred temperature and humidity, thus enhancing soil porosity. We allowed 17 young Lasius niger ant colonies to excavate nests in soil columns exposed to three surface temperatures (mild, n = 5; medium, n = 6; and high, n = 6) for 100 days. We measured the amount of soil excavated weekly and took X-ray scans of the soil column on Days 7, 14, 28, and 88 to characterize the three-dimensional structure of the nests (depth, shape, volume of chambers and tunnels). We then collected the colonies and measured their growth during the experiment, and the size and weight of workers. Ants reacted to surface temperature. Colonies exposed to medium and high temperatures excavated larger and deeper nests than those exposed to mild temperature. Nests excavated under high and medium temperatures had the same maximal depth, but chambers were located deeper in the former, which were further characterized by the refiling of some of the upper chambers. Colonies grew well in all treatments, although less under mild temperature. They produced normal-sized workers despite differences in surface temperature. Overall, these results suggest that ants exposed to higher temperatures live in deeper chambers. This study shows that surface temperature affects ant nest architecture, confirming its status as extended phenotype and highlighting its flexibility over time, which has in turn consequences on soil porosity.

PEEK Interference Screws Show Significant Tunnel Enlargement After ACL Reconstruction and is Comparable to Adjustable-Length Loop Cortical Button Fixation

BackgroundIt is unclear whether the use of polyetheretherketone (PEEK) interference screws for anterior cruciate ligament (ACL) reconstruction leads to postoperative tunnel enlargement. Femoral tunnel enlargement was further compared with adjustable-length loop cortical fixation.MethodsEighteen patients with ACL reconstruction using hamstring grafts were retrospectively divided into two groups. Eleven patients were treated with the ACL reconstruction technique using a PEEK interference screw for femoral graft fixation. Seven patients received adjustable-length loop cortical buttons for femoral fixation. Tibial ACL graft fixation was performed using PEEK interference screws. Tunnel volume changes were assessed using computed tomography (CT) scans performed after surgery (100%) and after 1 year. The maximal tunnel diameter was measured.ResultsThe group with femoral screw fixation showed a mean tunnel volume change of 108.15 ± 13.7% on the tibial side and 124.07 ± 25.38% on the femoral side. The group with femoral button fixation showed a tunnel volume change of 111.12 ± 12.72% on the tibial side and 130.96 ± 21.71% on the femoral side. The differences in femoral tunnel volume changes were not significant (P = 0.562). Femoral tunnels with PEEK screw fixation showed significantly larger diameter after 12 months in comparison with button fixation (13.02 ± 1.43 mm vs. 10.46 ± 1.29 mm, P < 0.001).ConclusionsPEEK interference screws were associated with significant tibial and femoral tunnel enlargement. Femoral tunnel enlargement was comparable between PEEK interference screws and button fixation. Final femoral tunnel diameter was significantly larger with PEEK screw fixation in comparison to button fixation.

Analytical solution for tunnelling-induced response of an overlying pipeline considering gap formation

Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model tests. However, this phenomenon has seldom been considered in current analytical solutions. This study formulates a tensionless Winkler solution that could make allowance for gap formation in soil-pipeline interaction analyses. The solution is validated by comparisons with existing experimental measurements and two recognized analytical solutions. Also, its advantage over an existing Winkler solution is addressed. Further parametric studies reveal that the effects of gap formation on the response of a pipeline rely largely on the tunnel volume loss and the pipeline’s bending stiffness and burial depth. In general, a pipeline’s bending moments and subgrade reaction forces are more susceptible than its deflections to the gap formation.

РЕКОНСТРУКЦИЯ ПОПЕРЕЧНОЙ ЗАПЯСТНОЙ СВЯЗКИ В ЛЕЧЕНИИ СИНДРОМА ЗАПЯСТНОГО КАНАЛА. ОБЗОР ЛИТЕРАТУРЫ

Introduction. Carpal tunnel syndrome is a compression of the median nerve at the wrist, a common compression neuropathy of the upper extremities in medical practice. The most effective treatment for this condition is considered to be surgical and the most common approach is either dissecting the carpal ligament without subsequent stitching or reconstructing it. A study of the efficacy of transverse carpal ligament reconstruction approaches helps in the search for treatment improvement. The aim of the study is to compare the effectiveness and safety of different surgical techniques according to Russian and foreign literature sources containing information on the immediate and long-term results of treatment of patients with carpal tunnel syndrome using the transverse carpal ligament reconstruction method. Materials and methods. Scientific publications on the topic for 2013-2023 were studied. Results and discussion. It was found out that reconstruction of the transverse carpal ligament contributes not only to the increase of carpal tunnel volume, but also to normalization of biomechanics of carpal movements after the operation. Conclusion. Currently, there is no unequivocal evidence of significant advantages of reconstructing the transverse carpal ligament. The majority of authors consider reconstructive surgery effective in conditions of morphologically distorted median nerve or carpal tunnel as well as peculiarities of the patient history, which may require earlier restoration of the upper extremity functional state and ability to work.

Prediction of subsurface settlement induced by shield tunnelling in sandy cobble stratum

This study focuses on the analytical prediction of subsurface settlement induced by shield tunnelling in sandy cobble stratum considering the volumetric deformation modes of the soil above the tunnel crown. A series of numerical analyses is performed to examine the effects of cover depth ratio (C/D), tunnel volume loss rate (ηt) and volumetric block proportion (VBP) on the characteristics of subsurface settlement trough and soil volume loss. Considering the ground loss variation with depth, three modes are deduced from the volumetric deformation responses of the soil above the tunnel crown. Then, analytical solutions to predict subsurface settlement for each mode are presented using stochastic medium theory. The influences of C/D, ηt and VBP on the key parameters (i.e. B and N) in the analytical expressions are discussed to determine the fitting formulae of B and N. Finally, the proposed analytical solutions are validated by the comparisons with the results of model test and numerical simulation. Results show that the fitting formulae provide a convenient and reliable way to evaluate the key parameters. Besides, the analytical solutions are reasonable and available in predicting the subsurface settlement induced by shield tunnelling in sandy cobble stratum.