Indoor Test Research Articles

Design and rigid body dynamics analysis of a novel retractable drill bit used in casing-while-drilling

Utilizing the Geneva drive mechanism, an inventive retractable drill bit tailored for casing-while-drilling (CwD) applications was developed. This novel design allows the lower segment of the drill bit to be swung outward through rotation, facilitating to drill a larger hole and retrieved effortlessly by raising the drill tools. An exploration into the dynamic behavior of this retractable drill bit under varying drilling conditions was undertaken, focusing on parameters such as weight-on-bit, rotation speed, friction coefficient between the drill bit and rock, and lifting force. Findings from the investigation revealed that, under conditions of 20 kN weight-on-bit, a friction coefficient of 0.3, and a rotation speed of 30 rpm, the drill bit achieved full extension within 3.8 s. Notably, the movement speed of the lower drill bit was notably influenced by weight-on-bit, the friction coefficient, and lifting force, demonstrating accelerated movement with increased values of these factors. Rotation speed, however, exhibited negligible impact on the movement of the drill bit. An indoor experimental examination mirrored the outcomes obtained through simulations. Subsequent to numerical simulations and indoor testing, a large-diameter drill bit was produced and field tested, showcasing its capability to flexibly extend and retract during drilling, achieving an average drilling speed of 1.7 m/h.

Analysis of strength, durability, stability, and fatigue parameters of furniture doors and drawers using engineering design method

Mechanical behavior properties were investigated for cabinet-type cabinet doors in kitchen furniture and drawer bottoms and joints used as storage areas under load in accordance with relevant standards (BS EN 16122). In the first stage, values physical and mechanical for particle board (PB) and medium-density fiberboard (MDF) were determined. According to the test results in the second stage, it was determined that the doors assembled using a torque of 1.3 N/m in the door tests were less deformed than those assembled with 0.63 N/m. According to the finite element analysis and real test results carried out in the final stage, it has been determined that the vertical loading analysis applied on the doors coincides with the real experiments by 85%, horizontal loading by 84%, and slam shut by 50%. The doors didn’t pass the final stage durability test in real experiments, and the analysis results revealed that the deformation areas were the same as for real experiment. In the drawers; strength 85%, displacement 84%, and slam shut 94% overlap are represented. The drawers completed the durability test in real experiments, and in the analysis, it was determined that the deformation that occurred under high stresses was in the same areas.

Assessing bio-oil cutback asphalt for prime coat on semi-rigid base asphalt pavement: Lab experiment & indoor test section application

To analyze the potential utilization of bio-oil cutback asphalt (BCA) as an innovative permeable material, this study comprehensively evaluated the road performance of BCA. Infrared spectroscopy and fluorescence microscopy were employed to characterize the components' interaction mechanisms and storage stability within the BCA. The research also involved assessments of interlayer strength, unconfined compressive strength, and dynamic water scouring trials of the base layer. Subsequently, a comprehensive assessment of the road performance of BCA was carried out in conjunction with its application on the indoor test section. The microscopic test results revealed that bio-oil and the penetrant primarily enhanced the asphalt's flow and penetration properties through physical blending. Even after 28 days of storage, no phase separation occurred among the constituents in the BCA. Compared to conventional prime coat materials, the specimens treated with BCA demonstrated notably higher interlayer pull-off and shear strengths at the optimal sprinkling volume. Furthermore, applying BCA to the cement-treated base improved its early strength and erosion resistance. As a result, BCA plays a crucial role in enhancing the structural integrity of asphalt pavements with semi-rigid base layers.

Slope Deformation Mechanisms and Stability Assessment under Varied Conditions in an Iron Mine Waste Dump

The instability of geological slopes in mining environments poses a significant challenge to the safety and efficiency of operations. Waste Dump#2 at the Ziluoyi Iron Mine in China is a notable case study that highlights the challenges associated with sizable base slopes and large step heights. To address hidden hazards in the mine and the above issues, an inclusive investigation is carried out to examine the physical and mechanical properties of the soil–rock slope through indoor testing and analyze the deformation mechanisms of the slope using numerical simulations, taking various factors into account. The study reveals that the stability of Waste Dump#2 is deeply affected by weight, groundwater conditions, earthquake loading, and rainfall. To this end, the cohesion and internal friction parameters of the soil–rock slope are first determined through direct shear tests, which show a cohesion of 6.215 kPa at the top of the slope and an internal friction angle of 34.12°. By adopting GEO-SLOPE, 3D Mine, and AutoCAD software, stability calculations of the slope are performed, which give stability coefficients of 1.547 under normal conditions, 1.276 in rainfall, and 1.352 in seismic conditions. These results meet safety standards and ensure the safe and efficient operation of the mine.

The Height Pole: Measuring plot height using a single‐point LiDAR sensor

AbstractPlant canopy height is an essential trait for phenomics and plant breeding. Despite its importance, height is still largely measured by manual means with a ruler and notepad. Here, we present the Height Pole, a novel single‐point LiDAR (SPL)‐based instrument to measure and record plant and canopy height in the field quickly, reliably, and accurately. An SPL was mounted on the top of a pole and aimed downwards at an adjustable paddle that was positioned at the desired height. A custom app, written for Android OS, saved the plant height data from the SPL to a tablet. The Height Pole was tested against a ruler in the lab, in a field trial setting, and by multiple operators. Indoor and outdoor testing found no significant differences between a ruler and the Height Pole measurements. A test with five operators revealed that measuring, recording, transcribing, and digitizing were on average 20 s per plot slower with a ruler than with the Height Pole. The Height Pole required only one operator to measure and record data, reduced operator fatigue, and by directly writing the data to a .CSV file eliminated transcription errors. These improvements make it easier to collect crop height data on large experiments rapidly and accurately with low input costs.

Smartphone-based Vision/MEMS-IMU/GNSS tightly coupled seamless positioning using factor graph optimization

With the diversification of functionalities and enhancement of performance in smartphones, low-cost GNSS chips, Micro-Electro-Mechanical System (MEMS) inertial measurement units (IMU), and cameras have become essential hardware components. Moreover, the computational power provided by smartphones for data processing has also become more robust. The fusion of multiple sensors in smartphones for positioning has emerged as a trend. In order to further enhance the positioning performance of smartphones in complex environments, this paper proposes a smartphone-based Vision/MEMS-IMU/GNSS tightly coupled integration for indoor-outdoor seamless positioning. Factor graph optimization is employed to combine observations from monocular vision, MEMS-IMU, and GNSS. To solve the unstable timing of current smartphone sensors, we present a GNSS-to-VIO time synchronization method. Furthermore, an adaptive positioning mechanism is devised based on the presence or absence of GNSS signals, allowing indoor and outdoor environment to switch. The proposed method is validated by integrating smartphone VIO with both smartphone built-in GNSS and high-performance geodetic GNSS receivers. The test results of the complex outdoor environments demonstrate that the proposed method significantly enhances GNSS positioning performance. The positioning accuracy of the proposed method using geodetic GNSS receiver is superior to that using smartphone GNSS. In outdoor environments, our method enables positioning accuracy of smartphone to improve 29.4, 53.0 and 69.9 % in three directions compared to single point positioning. Indoor and outdoor tests verified that the proposed method can provide continuous and reliable positioning in alternating interrupted and restored GNSS signals.

Study on shrinkage and creep effect of steel truss-stiffened continuous rigid frame bridge considering variable temperature and relative humidity

In this study, indoor-outdoor comparison tests of shrinkage and creep were carried out in northwest China. The experimental results were compared with commonly used models of shrinkage and creep, some of which have adapted different methods for temperature and humidity correction. A finite element model for a continuous rigid-frame bridge with steel truss bracing was established. The calculated values from different shrinkage and creep models were then compared with the measured deflection values. An analysis was conducted to determine the influence of variable temperature and humidity on the long-term mechanical behavior of the steel truss-stiffened continuous rigid-frame bridge.The results show that when the concrete reaches the age of one year, the creep coefficient for the outdoor environment is 18.5% smaller than that in the indoor environment, while the outdoor shrinkage strain is 16.0% smaller. The CEB 90 model agrees best with the indoor test results. The corrected shrinkage and creep model (CSCM) is the closest to the outdoor test results, and the fib2010 model ranked second. The predicted values from CSCM exhibit the best agreement with the measured deflection values after the bridge completion. The CEB 90 model's predicted values for deflection of the main girder, longitudinal displacement of the pier, the maximum stress in steel trusses, and prestressing loss are lower than those in the CSCM after 20 years of construction, indicating that the influence of temperature and relative humidity variations on shrinkage and creep effect of the bridge can not be negligible.

An Experimental Investigation of the Effects of Block Proportion on Bimrocks, Considering Different Block-to-Matrix Strength Ratios.

The rock block proportion is one of the most important factors affecting the mechanical properties of bimrocks. Under different block-to-matrix strength ratios, the influence of rock block proportion is different. To explore the influence of rock block proportion on the mechanical properties of specimens under different block-to-matrix strength ratios, a new indoor test method for making bimrocks was proposed. A uniaxial compression test and a direct shear test were carried out on specimens with different rock block proportions. The results show that this method can control the block-to-matrix strength ratio well, and the influence of rock block proportion is obviously different under different block-to-matrix strength ratios. The strong matrix sample will decrease significantly after reaching the peak compressive strength, while the weak matrix will decrease slowly after reaching the peak strength. The rock block proportion is negatively correlated with the uniaxial compressive strength of strong matrix samples (the reduction was 12.53%) and is positively correlated with the uniaxial compressive strength of weak matrix samples as a whole, but it changes when block proportion is more than 50%. With the increase in normal stress and rock block proportion increases from 30% to 60%, the shear failure zone of the weak matrix sample increases, and the cracks are inclined, while the strong matrix sample has more secondary cracks. The results of this study also show that the effect of volumetric block proportion (VBP) on the internal friction angle and cohesion of the sample is less related to the block-to-matrix strength ratio.

The evolution law of deviatoric stress and asymmetric control technology in roadways during panel mining through overlying residual coal pillars

Close-distance coal seams (CDCS) are widely distributed, and the layout of the upper and lower panels can be divided into “=” type and “+” type. The “+” superposition of upper and lower coal pillars in CDCS caused strong mine pressure, but there are few studies on the panel crossing residual coal pillars (RCP) when the upper and lower coal seams are “+” type layout. In view of the special spatial position (“+” type layout), this paper takes the typical panel 4-301 of a particular mine as the project indagation background and studies mining and crossing the overlying coal pillars by dint of field measurement, numerical simulation, indoor test, and engineering application. Compared with vertical stress or horizontal stress alone, the indexes of deviatoric stress and plastic zone can reflect the failure evolution of surrounding rock more comprehensively. Hence, this paper analyzes the expansion form of the plastic zone and the variation law of deviatoric stress before and after mining influence in the underlying mining roadway. The research results show that: (1) There is a sub-peak zone of deviatoric stress under the RCP. The deviatoric stress is bimodal in the range of 9 m below. After the peak value decays to 7.4 MPa, it changes to a single peak located in the area directly below the middle of the RCP. (2) The maximum plastic zones of the roof and two ribs of the roadway below the RCP are 3.4 m and 5 m, respectively. The crest value of deviatoric stress reaches 10 MPa. As the distance between the panel and the RCP decreases, the shape of the high deviatoric stress area presents the evolution law from the “ellipse” of the roof → the “crescent” of two ribs → the “cochlea” of the tips of the ribs. (3) When the mining of the underlying panel is 10 m, 0 m, or − 10 m away from the RCP (without passing through the RCP). The crest value of deviatoric stress within 5–10 m in advance of the roadway increases in turn. However, the peak value is significantly reduced when it is − 20 m away from the RCP (through the RCP). The crest value of deviatoric stress of two ribs decreases in turn along the panel rib → section coal pillar rib → solid coal rib. Based on this, the underlying 45 m of the RCP is divided into area I (10 m), area II (overlapping area 20 m), and area III (15 m) based on the degree of disturbance. And propose the technical scheme of asymmetric combined control in different zones by using asymmetric channel steel truss anchor cable for the top-ribs of areas I and III, and top-ribs asymmetric channel steel truss anchor cable + door-type support in area II. On-site project practice shows that the partitioned control technology successfully resisted the roadway instability and failure caused by the dynamic-static superimposed stress disturbance under the RCP and realized the primary support of the sectional coal roadway. The conclusion provides technical support and scheme design for the partitioning support of roadways under similar “+” type cross‐panels.

CFD Simulations of Small Particle Behavior with Blower-Driven Airflows in Single-Family Residential Buildings

Inhaling airborne droplets exhaled from an infected person is the principal mode of COVID-19 transmission. When residential energy efficiency workers conduct blower door tests in occupied residences with a COVID-19-infected occupant potentially present, there is a concern that it could put the workers at risk of infection with massive flows of air being generated by the tests. To minimize this risk, computational fluid dynamics (CFD) simulations were conducted for four prototype houses to develop guidelines for workers to follow during their service visits. The CFD simulations visualized the movements and evaluated the residence time of small particles released at certain locations under a series of scenarios representing situations that are likely to be encountered during in-home energy efficiency services. Guidelines were derived from the simulated tracks of droplets to help to increase the safety of the worker(s).

Study on Shear Slip Characteristics of Sandstone Plane Joints under Normal Dynamic Load Disturbance

Abstract Rock joints are susceptible to slip instability due to dynamic load disturbances such as blasting, earthquakes, and fracturation. A series of direct shear tests under the dynamic load were conducted on sandstone plane joints using the RDS-200xl. The work investigated the effects of normal static loads and normal dynamic-load frequencies and amplitudes on plane joints. Besides, the following items were proposed, that is, the peak-to-valley response rate, shear velocity vibration dominant frequency, shear-stress reduction coefficient, and discrete element numerical simulation method for plane-joint direct shear tests. The results were as follows: (1) The normal dynamic load frequency played a role in attenuating the shear stress amplitude with a threshold value of 0.5 Hz. (2) The shear velocity of the plane joint was completely controlled by the high normal dynamic load frequency. Their vibrational dominant frequencies were identical. (3) The amplitude of shear stress increased, and the median stress decreased with the increased normal dynamic load amplitude. The reduction-coefficient equation for sandstone plane joints was proposed to evaluate the shear stress under the normal dynamic load disturbance. (4) The shear-stress hysteresis phenomenon existed in the plane joints under the normal dynamic load, which required excessive shear displacements to reach peak shear strength. The peak shear displacement increased with the increased normal static load. Numerical simulations and indoor tests showed that high- and low-shear-velocity regions were the main reason for shear-stress hysteresis. The findings are conducive to revealing the shear destabilization mechanism of rock joints under dynamic load disturbance.

Study of longitudinal deformation profiles in high-ground-stress mega-section tunnels based on the Hoek–Brown criterion

In rock tunnel construction, the analysis of rock deformation characteristics is an essential aspect of the overall safety evaluation. In this study, the high-ground-stress section of the Tongzi tunnel was taken as the research object and the longitudinal wave velocities of the disturbed and undisturbed areas of the surrounding rock were measured using on-site drilling to determine the disturbance range of the surrounding rock excavation. The uniaxial and triaxial compressive strengths of the rocks sampled in the field were measured through indoor tests. Through a combination of the field acoustic test and indoor test results, the Hoek–Brown (H-B) failure criterion parameters of the surrounding rock were quantitatively obtained. A numerical model was developed for the analysis, and the following conclusions were drawn: At the pre-deformation stage, the influence of the crown settlement, horizontal displacement, and the tunnel face extrusion deformation were all within the range of one times the tunnel diameter. The location and area of the first tunnel face influenced the extent of the surrounding rock’s pre-deformation. A more pronounced effect on the pre-deformation of the tunnel crown settlement was obtained the closer the first tunnel face was to the tunnel crown. In addition, the closer the first tunnel face was to the arch waist, the more pronounced the impact was on the pre-deformation of the horizontal displacement, and the pre-deformation increased exponentially with the increase in the significance of the excavation area of the first tunnel face. The deformation varied in tunnels that had been excavated using different construction methods. The three-step method employed in this study resulted in the most considerable deformation, followed by the CD method, and the double-side heading method resulted in the smallest deformation. The results show that increasing the number of working faces and using small cross-sectional staggered slot excavation are beneficial to tunnel stability. The field monitoring data are generally consistent with the numerical simulation results, providing a degree of validation for the numerical simulation results. The intrinsic model used in the numerical simulation influences the simulation results. When compared with the Hoek–Brown principal structure model, using the Mohr–Coulomb central structure to simulate the high-ground-stress rock tunneling may result in more considerable elevation arch uplift and tunnel face extrusion deformation. Therefore, it is more reasonable to use the Hoek–Brown principal structure model.

Study on scale effect and particle crushing characteristics of continuously graded coarse-grained soil

The scale effect is an inevitable engineering challenge in dam construction, and the scale test is an effective means to characterize the dam material properties. In this article, the scale effect of the large coarse-grained soil is investigated based on physical and numerical tests. Firstly, the indoor and field compression test apparatuses are optimized to rectify the effect of barrel sidewall friction on the compressibility modulus during the tests. Then, the sample preparation standard for different scaled samples is determined by large-scale relative density tests in the field. Finally, based on indoor and field large-scale compression tests, the variation of the scale effect is investigated, and the particle crushing characteristics of the continuously graded aggregate sample are analyzed. The crushing characteristics of the continuously graded aggregate sample differ from those of the single-particle and the single size-group aggregate sample (a small range of particle sizes). Compression tests of the single-particle, single size-group aggregate, and continuously graded aggregate sample are characterized by overall splitting, overall splitting and local crushing, and local or angular crushing, respectively. The coordination number is the main reason for the difference in crushing characteristics of different test samples. The relationship between different particle sizes and strengths of continuously graded aggregate sample is investigated. The results of the study can provide a reference for recognizing the scale effect of large coarse-grained soils and evaluating compaction quality in the field.

A continuous-discontinuous deformation analysis method for research on the mechanical properties of coarse granular materials

The mechanical properties of coarse granular materials play a crucial role in the safety of rockfill dams. From a mesoscopic viewpoint, the macroscopic mechanical properties of these materials are a result of the interactions between particles and the progression of particle breakage. Traditional continuum-based numerical methods struggle to accurately analyze the mechanical properties of coarse granular materials. Discontinuous deformation analysis (DDA) is a more suitable algorithm for studying these properties due to its significant benefits in block displacement mode and open-close iteration for contact handling. In this paper, a continuous-discontinuous deformation analysis method (CDDA) based on the conventional DDA is developed for the numerical investigation of coarse granular materials' mechanical properties. This method incorporates critical kinetic damping, multi-stageloading, stricter displacement convergence criteria and particle breakage simulation. It can provide a comprehensive representation of deformation, particle breakage, force chain, shear zone, and stress–strain curve evolutions. The CDDA results are found to be consistent with indoor test results and can more effectively disclose the deformation and failure mechanism of coarse granular materials. Furthermore, CDDA is employed to examine the impacts of particle size and end friction, leading to valuable insights regarding these effects.

Development and experimental evaluation of new building air leakage measurement methods: measurement of interior air leaks and comparison to conventional methods

Building air leaks (both through exterior and interior surfaces) can have a significant impact on energy consumption, indoor air quality, fire safety, and moisture accumulation affecting structural durability. Blower door testing has been used to measure leaks in buildings, but commonly used testing methods do not directly measure interior leaks. In this paper, new testing methods (guarded interior test and zonal multipoint pressure testing method) are presented that directly measure these interior leaks, utilizing common blower door equipment for both single and multi-point testing. These new methods are compared to conventional methods in terms of the information provided, limitations and time/effort needed. In addition, building leak measurement results are analyzed to reveal (a) coupling between power law model values (exponent and coefficient) for an ensemble of buildings, (b) the error in using single point testing when estimating low pressure leakage, and (c) how building power law models vary from low to high pressure ranges.

Study on the Stability of Cut Slopes Caused by Rural Housing Construction in Red Bed Areas: A Case Study of Wanyuan City, China

The red beds that are widely distributed in hilly areas in eastern Sichuan Province are inevitable rock and soil masses in engineering construction. In order to obtain a larger building area, engineering slope cutting is quite common in red bed hilly areas. Engineering slope cutting destroys the inherent stability of a slope and causes geological disasters. In order to practice the concept of sustainable development and explore ways to develop and utilize land resources reasonably and reduce the possibility of geological disasters caused by engineering slope cutting, this paper took the slope cutting sites caused by rural housing construction in the red bed area of Wanyuan City as research objects. The internal and external factors affecting the stability of the cut slopes were summarized through a field investigation, and two typical slopes were selected for analysis. Sampling and indoor tests were conducted to obtain the geotechnical parameters. Geo Studio software (2018 R2) was employed to establish numerical models, simulate the stress and strain distributions, and compute stability coefficients under different slope cutting conditions at the same time. Based on field investigations and numerical simulations, the three main failure modes of shallow landslides caused by slope cutting were summarized, and the evolution process of slope landform accelerated by slope cutting activities was deduced. In an engineering application, the functional relationship between the cutting height and the stability coefficient was fitted. It was found that the critical cut height values of soil slope were 6.3 m, 6.2 m, 5.2 m, and 2.6 m at slope of 10°, 20°, 30° and 40°, respectively; the critical cut height values of rock–soil mixed slope were 9.3 m, 6.5 m, 5.9 m, and 2.2 m at slope of 10°, 20°, 30° and 40°, respectively. The research findings can be used to prevent and manage the hazards caused by slope cutting in this study area.

Infiltration Models in EnergyPlus: Empirical Assessment for a Case Study in a Seven-Story Building

The current decarbonization transition to be achieved by 2050 according to the European Council has given great prominence to the use of Digital Twins as tools for energy management. For their correct operation, it is essential to control the uncertainties of the energy models, which lead to differences between the measured and predicted data. One of the key parameters that is most difficult to assess numerically is air leakage. The existent infiltration models available in EnergyPlus were developed to be applied in low-rise residential buildings with fewer than three stories. Therefore, it is common to rely on air leakage equations employing predefined coefficients. This research presents an empirical assessment of the performance of two EnergyPlus air leakage models, the “Effective Leakage Area” and the “Flow Coefficient”, in predicting dynamic infiltration within the attic of a seven-story building. Blower door tests, along with the application of CO2 tracer gas, were conducted to establish coefficients for the models. Then, they were evaluated in three independent periods according to the criteria established in the American Society for Testing Material D5157 Standard. Those models that only used in situ coefficients consistently met the standard across all three periods, demonstrating for both equations their accurate performance and reliability. For the best model derived from tracer gas data, the R2 and NMSE values are 0.94 and 0.019, respectively. In contrast, the model developed using blower door test data and EnergyPlus default values presented a 64% reduction in accuracy compared to the best one. This discrepancy could potentially lead to misleading energy estimates. Although other software options exist for estimating infiltration, this study specifically targets EnergyPlus users. Therefore, these findings offer valuable insights to make more informed decisions when implementing the infiltration models into energy simulations for high-rise buildings using EnergyPlus.

Simulation analysis and experimental testing of the grading performance of small potato grading device

AbstractExisting potato grading device has a complex structure and a large volume, which is not suitable for small‐scale potato farmers. However, traditional manual grading methods not only have low efficiency but also high labor costs. This article developed a small movable rotating plate (MRP)‐type potato grading device, and the influences of three factors (the height of the horizontal slide, the tilt angle of the inclined slide, and the chain speed) on the grading efficiency and accuracy were investigated using the discrete element method and virtual orthogonal experiments. It was found that the horizontal slide height of 185 mm, the inclined slide tilt angle of 3.5°, and the chain speed of 0.9 m/s yielded the optimal grading efficiency (13.84 t/h) and grading accuracy (94.11%). Finally, the potato grading process was tested and validated through indoor tests, and the optimal grading accuracy was 91.04%. The grading accuracy deviation between the test and simulation results was less than 8%.Practical ApplicationCurrently, most commercial potato grading machines are designed for large‐scale farms, which are not suitable for developing countries. The potato grading device designed in this article can not only be used independently by small‐scale farms, but also be integrated with potato combine harvesters to achieve potato harvest and grading joint operations. This grading device has a simple structure, small footprint (1700 × 1200 × 840 mm3), and a very low cost ($600). With a high grading efficiency and accuracy, it can significantly improve the grading productivity of small and medium‐sized potato farmers in developing countries, reduce the production costs, and save labors.

Intelligent residual film recovery machine monitoring and control system

Domestic residue recovery machines in China still follow the traditional towed mechanical model, lacking automation and intelligent features. Under the key R&D project of Xinjiang Autonomous Region, our team has developed integrated intelligent agricultural machinery for cotton straw crushing and residue recovery. This research covers the monitoring and control system, including PLC control and communication, working parameter monitoring and adjustment, algorithmic control of electro-hydraulic actuators, and human-machine interface display. Compared to traditional models, this machine replaces the conventional chain-driven mechanical structure and diesel tractor traction power with a fully hydraulic integrated suspension drive and power system. Sensors, PLC, and a touch screen are utilized for real-time monitoring and display of parameters. Hardware components like electromagnetic switch valves, electro-hydraulic proportional valves, hydraulic cylinders, and software elements such as PLC programs and intelligent control algorithms are employed for electro-hydraulic switching and proportional control of certain working parameters and mechanisms. All parameter information is consolidated in the PLC host and expansion modules and displayed and controlled on the human-machine interface. The system was installed on the first-generation machine for indoor testing, revealing that the monitoring and control system used on the first-generation machine achieves parameter detection and adjustment of the actuating mechanisms. It incorporates more advanced functions compared to traditional residue recovery machines. However, there is still ample room for improvement in the overall intelligence of the machine. The control system’s structure requires adjustment, and certain functionalities of the overall mechanical structure and working components need optimization or upgrading. Detailed enhancements to the entire system will be made in the next-generation machine.

Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature.

The southwest region of China has abundant groundwater and high-temperature geothermal energy. Carbonaceous shale, as one of the typical surrounding rocks in this region, often suffers from deterioration effects due to the coupled action of groundwater chemical erosion and high temperature, which affects the long-term stability of tunnel engineering. In order to investigate the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, carbonaceous shale from a tunnel of Lixiang Railway in Yunnan Province was taken as the research object. The microstructure and mineral composition of the samples before and after chemical erosion were obtained with a scanning electron microscope-energy dispersive spectrometer and an X-ray diffraction test. Then, triaxial compression tests were conducted on the samples under different time points and different temperature effects of chemical erosion, and the stress-strain curves and the deterioration laws under a single factor were obtained. An improved numerical simulation method based on the parallel bond model was developed, which can account for the coupled effects of chemical erosion and high temperature on the rock. By simulating the triaxial compression test of carbonaceous shale, the deterioration law of carbonaceous shale under the coupled action was discussed. The results show that chemical erosion has a significant deterioration effect on the triaxial compressive strength of carbonaceous shale, and the degree of deterioration is related to the erosion time. In the first 30 days of erosion, the triaxial compressive strength of carbonaceous shale decreased by 11.38%, which was the largest deterioration range. With the increase in erosion time, the deterioration rate gradually decreased; temperature had a significant threshold effect on the strength of carbonaceous shale, and a clear turning point appeared at about 200 °C. By simulating the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, it was found that the longer the duration of chemical erosion, the stronger the temperature sensitivity of carbonaceous shale, and the more serious the loss of compressive strength during the heating process. When the temperature was low, the strength of carbonaceous shale changed little, and some samples even showed an increase in strength; when the temperature was high, the strength of carbonaceous shale decreased significantly, showing deterioration characteristics. The numerical simulation method was compared and verified with the indoor test results, and it was found that the numerical calculation had a good agreement with the test results.