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The study was conducted to develop an optimized design method for the rapid arrangement of non-equidistant thrust systems in shield machines under complicated geological formation conditions, aiming to enhance the efficiency of thrust system reconfiguration. Firstly, mechanical principles for the rapid deployment of non-equidistant thrust systems were set, grounded of force transmission in the thrust system. Secondly, based on the principles, the optimizing model was propose on the minimal displacement and characteristics for the uniform arrangement was discussed in detail. Thirdly, the model was applied to a shield machine with a 6.15-m diameter and a 24-jack thrust system, where the stability was evaluated using the CV standard. Finally, a virtual prototype of the optimized thrust system was set up in ADAMS (Automatic Dynamic Analysis of Mechanical Systems) to validate the model. The results validate that the proposed layout optimization not only offers higher stability compared to traditional equidistant layouts but also meets the requirements for rapid deployment under complex geological conditions. This provides theoretical support for improving the deployment efficiency of the non-equidistant thrust system in shield machines operating in complex geological environments.

We present a multiscale seismic attenuation tomography of a seismotectonically complex region in northern Italy hosting the well‐characterized Collalto Underground Gas Storage (UGS). Beyond its specific relevance, this site provides a natural laboratory for assessing the ability of attenuation imaging to distinguish fluid‐rich zones from highly strained, failure‐prone volumes. We integrated scattering and absorption tomography models: scattering anomalies, between the two principal thrusts, highlight localized strain near fault tips; absorption tomography images the shallow UGS and reveals a deeper fluid‐saturated volume. Seismicity concentrated around this deeper anomaly, exhibiting a pulsatory temporal pattern, suggests a fluid‐driven role in the deformation processes. These findings show that attenuation tomography, combined with multiscale and complementary geophysical models, can resolve critical subsurface features related to fluids and strain. The approach is broadly applicable to geothermal and volcanic contexts and supports seismic hazard assessment in tectonically active regions where natural and anthropogenic processes may interact.

In tunnel boring projects, wear and tear in the tooling system can have significant consequences, such as decreased boring efficiency, heightened maintenance costs, and potential safety hazards. In this paper, a fault diagnosis method for TBM tooling systems based on SAV−SVDD failure location (SSFL) is proposed. The aim of this method is to detect faults caused by disk cutter wear during the boring process, which diminishes the boring efficiency and is challenging to detect during construction. This paper uses SolidWorks to create a complete three−dimensional model of the TBM hydraulic thrust system and tool system. Then, dynamic simulations are performed with Adams. This helps us understand how the load on the propulsion hydraulic cylinder changes as the TBM tunneling tool wears to different degrees during construction. The hydraulic propulsion system was modeled and simulated using AMESIM software. Utilizing the load on the hydraulic propulsion cylinder as an input signal, pressure signals from the two chambers of the hydraulic cylinder and the system’s flow signal were acquired. This enabled an in−depth exploration of the correlation between these acquired signals and the extent of the tooling system failure. Following this analysis, a collection of normal sample data and sample data representing different degrees of disk cutter abrasions was amassed for further study. Next, an SSFL network model for locating the failure area of the cutter was established. Fault sample data were used as the input, and the accuracy of the fault diagnosis model was tested. The test results show that the performance of the SSFL network model is better than that of the SAE−SVM and SVDD network models. The SSFL model achieves 90% accuracy in determining the failure area of the cutter head. The model effectively identifies the failure regions, enabling timely tool replacement to avoid decreased boring efficiency under wear conditions. The experimental findings validate the feasibility of this approach.

Over the decades, polar satellite launch vehicles and geosynchronous launch vehicles have utilized variants of the Vikas engine for numerous space operations. The pitching control for those launch vehicles is achieved by gimbaling the Vikas engine nozzle up to ± 4° with mechanical actuating parts. This research investigation dealt with the design modification, analysis, and estimation of performance parameters in the modified Vikas nozzle configurations intended for fluidic thrust vectoring control. Hence, the technique of interest in this investigation was to assess the effects of the fluidic throat skewing technique in an adapted nozzle configuration of the Vikas nozzle. The distinct design configurations were initially iterated with the design of experiments (DOE) method to estimate and adopt an optimum nozzle configuration with higher thrust vectoring effectiveness. The computational analysis utilized the k-e Reynolds-averaged Navier-Stokes (RANS) numerical model. The flow characteristics of the resolved nozzle configuration were analyzed and validated under three distinct sonic mach freestreams. Finally, air was employed as the secondary fluid in the injector plenum, and the analysis was carried out by varying the secondary mass injection rates. The analysis results depicted that the implemented fluidic injection thrust vectoring approach was significantly effective by achieving ± 5° of tilt with a system thrust force ratio of 0.9190 for 9% of secondary mass flow rate injection.

The tunnel boring machine (TBM) is widely used in tunnel construction projects. The thrust system plays a crucial role to drive the machine ahead and support gripper shoes stably while tunneling. More and more attention has been paid to the pressure and velocity regulation efficiency as the TBM advances in complex rock conditions to ensure the stabilization of the tunneling process. A thrust hydraulic control system, assembled with a proportional pressure reducing valve, is established with system operating parameters. The mathematical model of the thrust electro-hydraulic system is revealed. To improve the control characteristics of the thrust system, a self-tuning fuzzy PID controller is introduced in the pressure and velocity regulation procedures. After that, tests on a Φ2.5 m scaled TBM test rig are carried out. The test results show that the thrust system adopting the fuzzy PID controller results in less oscillation and a smoother regulation process. It takes less time to reach the target goal of pressure regulation with less vibration during the pressure regenerating periods, and both systems of conventional PID controller and fuzzy PID controller are qualified in velocity regulation movements. The proposed control methods show better benefits in reduction of vibrations and shorter time of regulation to stable conditions, which extends the machine’s life and affects the acceleration of the tunneling process.

We present a geological survey of the southwestern sector of the Mt. Massico (southern Apennines), which allowed us to reconstruct the stratigraphy and tectonic architecture of this area. The Mt. Massico is a key area to study the out-of-sequence thrusting stage that affected the southern Apennine chain since the late Miocene, which despite the wide occurrence of these structures in the whole chain, is a tectonic process up to now poorly investigated. This area deserves to be analyzed also for the occurrence of marble detritus within a wedge-top basin deposit, representing the only place in the southern Apennines, where such a kind of metamorphic rocks occurs. Historically, this area is known for the extraction of an ornamental stone, named Mondragone Marble. The marble is hosted as olistoliths and clasts within the deposits of the Caiazzo Fm. unconformably covering a Jurassic–middle Miocene succession, mostly made of shallow water-to-deep-basin carbonates. The wedge-top basin deposit mainly consists of a chaotic assemblage of conglomerates, olistostromes, and olistoliths of Meso-Cenozoic limestones, deep-basin rocks, and marbles, embedded in a quartzose matrix. The structural setting results from a polyphase deformation related to the superposition of two thrust systems. The first thrust system includes a duplex verging to east, with the Cenozoic carbonates thrusted onto the Caiazzo Fm. and the roof thrust cut by several breaching thrusts. The late thrust system encompasses ramp-dominated faults verging to the north. Folds, minor thrusts, and S–C structures are associated with the major compressional structures. To date the Caiazzo Fm. and put a temporal constraint to the thrust fault activity, we performed a nannoplankton content analysis that furnished, for the base of this deposit, an age not-older than the upper Tortonian. These out-of-sequence thrusts hence have acted since the late Miocene. Similar structures are widespread in the southern Apennines and are interpreted as the surficial expression of envelopment thrusts formed at deeper structural levels with respect to the thrust front. We envisage that the marble and plutonic supply was provided by the Mesomediterranean continental crust in the late Tortonian when this microcontinent was passing close to the Apennine Platform domain during its orogenic migration toward SE.

The thrust system, an important subsystem of a tunnel boring machine (TBM), primarily provides thrust force and adjusts TBM’s attitude in real time. In the tunneling process, only controlling the thrust speed causes pressure oscillations, increases soil deformation, and leads to surface subsidence or upheaval. Conversely, solely relying on pressure control causes fluctuations in speed, making it difficult to ensure that the deviation between the designed tunneling axis (DTA) and the actual tunneling axis (ATA) remains within the permissible range. Due to the increase in geological complexity and higher construction quality standards, primarily relying on single-mode speed or pressure control has become inadequate to meet operational demands. Therefore, to realize higher safety and precise trajectory tracking, it is necessary to ensure speed and pressure compound control for thrust systems. This paper proposes a novel adaptive sliding mode control (ASMC) strategy for thrust systems, which is composed of a proportional pressure relief valve (PPRV) and a proportional flow control valve (PFCV). Firstly, PPRV and PFCV are modeled as a second-order system and an ASMC is employed to control the pressure and speed. Next, to assess the performance of the ASMC controller, simulation experiments were conducted under various conditions, including speed regulation, sudden changed load, and disturbed load. The simulation results indicate that compared to the Proportion–Integral–Differential (PID) controller, the ASMC controller shows almost no overshoot in speed and pressure control during the initial stages, with the response time reduced by approximately 70%. During speed regulation process and sudden changed load process, the response time for both speed and pressure control is shortened by about 80%. In the disturbed load process, the ASMC controller maintains pressure stability. In conclusion, the ASMC controller significantly improves the response speed and stability of the thrust system, exhibiting better control performance under various operating conditions.

Karst is the most common ore-controlling structure in Mississippi Valley-type (MVT) Pb–Zn deposits. However, the formation process of karst caves that contain ores and their related Pb–Zn mineralization in fold-thrust belts is poorly understood. The Changdong MVT Pb–Zn deposit is hosted by karst caves located in the fold-thrust system of the Simao basin, Sanjiang metallogenic belt, Tibetan Plateau. The Changdong deposit is an ideal natural laboratory for studying the effects of karst on Pb–Zn mineralization in MVT deposits. The ore bodies in this deposit are hosted by a large-scale carbonate breccia and bedded sediments belt within the late Permian limestones, which are situated in the hanging wall of the regional Longshu thrust fault. The δ13CV-PDB values of the limestone fragments from the breccias range from − 4.2 to 4.1‰. They are similar to those of overlying limestone strata, indicating that the fragments were mainly derived from autochthonous limestones in the overlying strata. Energy-dispersive spectroscopy analysis indicates that the bedded sediments and the matrices of the carbonate breccias contain K–Al silicate clay minerals, quartz, rock fragments, and calcite fragments. Detrital zircons from bedded sediments contain five discrete age populations ranging from the Jurassic to the Paleoproterozoic, indicating that the matrix materials were derived from the weathered sediments of metamorphic and magmatic rocks along the western margin of the Simao basin. Bedded sediments dominated by exogenous materials are actually speleothems. When contextualized with recently published data placing the Changdong deposit formation in the early to middle Oligocene, our data suggest that the Changdong deposit formed within a meteoric paleokarst system. The Pb–Zn ores are hosted by the speleothems in the breccia belt and comprise microspherulitic or colloidal sphalerite and euhedral galena. The sphalerite and galena precipitated by filling voids and replacing calcite crystals in faded speleothems. The pyrite and galena δ34SV-CDT values from the Changdong deposit range from − 16.9 to 15.8‰, indicating a pre-existing H2S reservoir interpreted as a result of bacterial sulfate reduction (BSR). A three-stage process for the Changdong deposit was proposed as last. First, the Permian limestone was uplifted to the near-surface by regional thrusting during the India-Eurasia collision, and karst caves formed by meteoric dissolution. Second, a reduced sulfur trap formed by BSR in the paleokarst caves during continual regional compression. Third, metal-rich fluids migrated into the Changdong deposit via tensile faults formed during the transition from compressive stress to extensional strike-slip stress as a result of progressive rotation of the regional strain axes. The Pb–Zn sulfides were likely precipitated by low-temperature fluid mixing. This study provides new data to establish a geologically consistent framework for the evaluation of karst caves and related MVT Pb–Zn mineralization in fold-thrust systems.

This paper introduces a Python application for visualizing an imbricate thrust system. The application uses the traditional geologic information to create an HTML geological map with real topography and a set of geological cross-sections with the essential structural and stratigraphic elements. On the basis of the high geological knowledge gained during the last three decades, the Palomeque sheets affecting the Cenozoic Malaguide succession in the Internal Betic Zone (SE Spain) were selected to show the application. In this area, a Malaguide Cretaceous to Lower Miocene succession is deformed as an imbricate thrust system, with two thrusts forming a duplex, affected later by a set of faults with a main strike-slip kinematic. The modeled elements match well with the design of the stratigraphic intervals and the structures reported in recent scientific publications. This proves the good performance of this Python application for visualizing the structural and stratigraphic architecture. This kind of application could be a crucial stage for future groundwater, mining, and civil engineering management.

The thrust system of a tunnel boring machine plays a crucial role by driving the machine ahead and supporting the gripper shoes stably. A thrust hydraulic control system, assembled with a proportional flow control valve and a pressure relief valve, is established with system operating parameters. The mathematical model of a thrust electrohydraulic system is presented. To improve the control characteristics of the thrust system, a self-tuning fuzzy PID controller was introduced in synchronization motion control situations. To attain the best control parameters, three synchronization motion control systems were used to control the thrust propel cylinders. Tests on a Ø2.5 m scaled TBM test rig were carried out to verify the capabilities of the ISCS, SRSCS and CRSCS. Comparative tests were conducted, and the results showed that the thrust system adopting SRSCS achieved the least oscillation and the quickest response. The steady-state displacement error decreased by about 33.3% in contrast to the ISCS and CRSCS.