Pressure Plate Research Articles

Analysis of the pressure plate drive mechanisms of flat die-cutting presses

Analysis of the pressure plate drive mechanisms of flat die-cutting presses

Analysis of Railway Bridge Girder Installation and Construction Technology--Based on BIM Technology

Abstract The emergence of BIM technology has caused changes in the field of construction, which is of great significance to improving the construction technology and management level of roads and bridges. In this paper, the overall framework of the railroad bridge BIM model is constructed by utilizing several BIM software to display its corresponding geometric construction information and line information. Based on the relevant information, construction simulation technology is combined with BIM technology to propose a lean management model for a railroad bridge construction site. Specifically, it first checks the mechanical properties of the bridge plate to ensure the safety of its installation, and then optimizes the progress of the construction phase under the constraints of the construction site, realizes the deviation warning, and ensures the optimal completion of the construction project. The results show that the paving layer connection structure has an optimal load transfer effect in the range of 0-502kN. However, cracking at the critical point of the pressure plate can result in plastic deformation before. At the same time, the vibration of the abutment plays an important role in the safety of the overall bridge structure, and the abutment height of the bridge should be controlled within 40M. By optimizing the construction schedule of beams and slabs, the contract period can be shortened by up to 19 days, and the expected cost can be reduced by 760,000 yuan. The research results accumulate methods for applying BIM technology in the installation and construction stages of railway bridge beams and slabs.

Comparative study on suction obtained using the membrane filter method from triaxial apparatus and pressure plate apparatus

To investigate the stability of the earth embankments and slope failures during natural disasters, it is necessary to consider that soil is naturally unsaturated. Hence, it is essential to understand the variations of pore air pressure and pore water pressure, in terms of suction. The relationship between soil suction and soil moisture content is generally attained by soil water characteristic curve (SWCC), which is critically important in characterizing the mechanical behaviour of unsaturated soils. The SWCC is obtained from pressure plate apparatus by imposing the suction continuously by draining water from the saturated specimen and/or supplying water to unsaturated soil, which differs from the actual soil compaction process at the site. Therefore, the current study employs a methodology of suction measurement directly at a certain degree of compaction and degree of saturation using the membrane filter method in the triaxial apparatus, to meet the realistic conditions in the field. A comparative study has been done using SWCC with the imposed suction and the measured suction (Natural suction) at each compacted state. The results from both the methods exhibited an increase in the suction and air entry value with the increase in the degree of compaction, proving that an increasingly positive effect of suction contributed while increasing the density. Whereas the suction measured immediately after the compaction (Natural suction) in triaxial apparatus is more consistent with the suction imposed in the wetting process of SWCC. Further deep understanding of the microstructure behaviour of each compacted state and the SWCC is necessary.

Effect of targeted acetylation on wood–water interactions at high moisture states

Acetylation is a wood modification used to increase the durability. Although it is known that the wood moisture content is lowered, the exact mechanisms behind the increased durability are not known. However, since fungi need water in different locations for different purposes the location and state of water is most probably of importance in addition to the total moisture content. In a previous study, we used targeted acetylation to alter the wood–water interactions in different parts of the wood structure in water saturated and hygroscopic moisture states. The main range for fungal degradation is, however, between these moisture ranges. This study investigated the effect of targeted acetylation on location, state and amount of water at non-saturated, high moisture states using the pressure plate technique. Specimens were modified using acetic anhydride by two approaches: (1) uniform modification (2) interface modification acting on the cell wall-lumen interface. They were then conditioned to eight moisture states between 99.64 and 99.98% relative humidity in both absorption and desorption and the location and state of water was studied using Low Field Nuclear Magnetic Resonance, X-ray computed tomography and Differential Scanning Calorimetry. Capillary water was present at all the included moisture states for all specimen types, but the amounts of capillary water in absorption were small. Increasing degree of interface modification increased the amount of capillary water compared to untreated wood. In addition, the uniformly modified wood often had higher amounts of capillary water than the untreated wood. The amount of cell wall water was decreased by uniform modification, but slightly or not reduced by the interface modification. The combination of targeted modification and conditioning to high well-defined moisture states thus gave very different amounts of capillary water and cell wall water depending on the conditioning history (absorption or desorption) and choice of modification. This opens new possibilities for designing materials and moisture states for fungal degradation experiments of wood.

MEASUREMENT OF WATER RETENTION OF PEAT SOIL IN CANAL BLOCKING USING PRESSURE PLATE CHAMBER

Measuring air retention in constructed canal blockage is critical for determining changes in air content after canal blocking. The purpose of this study is to assess the influence of changes in levels on air retention values measured at three depths, namely 0-20 cm, 20-40 cm, and 40-60 cm, at four transect sampling stations created at a distance of 10 m to 260 m from the canal block. Changes in bulk density, porosity, and peat volume affect groundwater. Peat soil samples were collected from burned peatlands, and canal blocks were constructed. A pressure plate chamber was used to assess air retention. The findings of the investigation revealed that the air retention pattern of peat soil at 16 test sample locations was at maximum at PF 0.2 at each depth. At higher pressures (pF 2-4.2), peat groundwater is strongly bonded by peat soil particles. The average bulk density of peat is 0.2 2 and the porosity value is 86.79%. The higher the air content at each pF value has no influence on the porosity and bulk density values. Changes in air content between pF 2.0 and 4.2 lower average peat volume by 7.4%. The size of this value is assumed to be determined by the peat's type, maturity, and decomposition value

An experimental study of stress-dependent water retention behaviour of two lateritic clays with different minerals

Lateritic soils are associated with a high content of sesquioxides, which enhance the aggregation of fine particles. The formation of aggregates can induce significant changes in the pore size distribution (PSD) and consequently affect the hydro-mechanical behaviour of lateritic soils. The influence of mineral types on the extent of aggregation and the stress-dependent water retention behaviour of lateritic clays is not well understood. In this study, the stress-dependent water retention curves (SDSWRCs) of a compacted lateritic sandy fat clay with halloysite (i.e., GLH) obtained from Ghana were measured at different net vertical stresses using an improved stress-controlled pressure plate apparatus. The results were then compared with those of another lateritic sandy lean clay with goethite (NLG) obtained from Nigeria. Additionally, scanning electron microscopy (SEM) was employed to examine the microstructure associated with these soils. The experimental results show that GLH has a higher ability to retain water than NLG at any given suction, even though the former has a higher void ratio than the latter prior to the drying-wetting cycle. This is because of the presence of relatively small aggregates and small-size macropores in GLH, as revealed by SEM images. On the other hand, the water retention capacity of both soils reduces with elevated stress levels, except at net vertical stress of 120 kPa for GLH, with a corresponding decrease in the rate of desorption. Furthermore, the overall increase in the total degree of hysteresis measured is almost 2 times higher for NLG (i.e., 116%) than GLH (i.e., 72%) in the stress and suction range considered, contrary to the decreasing trends commonly reported in the literature. It was found that the sizes of aggregates in GLH reduced (‘finer soil’) as stress level increased and caused more water to be retained. Conversely to GLH, the aggregate size remained unchanged for NLG, as revealed by aggregate size analysis. This is mainly because of the differences in the strengths provided by the unique minerals in the two soils (i.e., halloysite for GLH and goethite for NLG) to the aggregates, due to the different parent rocks from which the soils were formed.

Determining the Bimodal Soil–Water Characteristic Curve of Fine-Grained Subgrade Soil Derived from the Compaction Condition by Incorporating Pore Size Distribution

The soil–water characteristic curve (SWCC) is a key constitutive relationship for unsaturated soil which can be unimodal or bimodal. For the fine-grained compacted subgrade soil with a bimodal pattern, the determination of SWCC is complicated and needs a wide-range suction measurement. In this paper, the bimodal SWCC of a subgrade soil derived from the compaction condition was measured and determined by incorporating pore size distribution. For this purpose, a series of laboratory tests were conducted, including the pressure plate method, filter paper method, and vapor equilibrium method, which were used to measure SWCC at the low, medium, and high suction range, respectively. The pore size distribution (PSD) data were obtained by mercury intrusion porosimetry (MIP) tests and used to predict SWCC. Based on the analysis of hydraulic paths and SWCC-PSD correlations, the SWCC of the subgrade soil should be determined to follow the actual hydraulic path. SWCC within a low suction range can be filled by PSD-based data to improve the fitting accuracy. Then, a graphical method is applied to predict the bimodal SWCC by combining the filter paper method, vapor equilibrium method, and PSD-based data. The prediction curves fit well with the test data for all selected compaction conditions. Furthermore, the prediction method can still provide good prediction performance in the absence of high suction section data, which is beneficial for the application of bimodal SWCC.

Equilibrium Moisture Content of High Strength Concrete Used in Hollow Core Slabs

The aim of this study was to measure equilibrium moisture content of hollow core slabs on both hygroscopic and capillary ranges. Because of the fabrication method of hollow core slabs, concrete grades and compacting methods used in the production differ from those used with reinforced concrete structures and elements. Test samples were taken from two slabs delivered by different manufacturers. Both slabs had similar geometry and were made of C50/60 grade concrete. Hygroscopic moisture equilibrium values were determined in climate chambers. Thin test specimens were used to perform tests within a reasonable time. Hygroscopic moisture equilibrium was measured at high relative humidities (RH), from 85 to 97 % RH. These measurements could be connected to the measurements of the retention curve done by a pressure plate. Measurements done in climate chambers and by pressure plate provided coherent results within the accuracies of these two methods. The results of two concrete slabs representing two different manufacturers differed significantly from each other, indicating the deviation of hygrothermal material properties even if the studied slabs were almost identical in many respects. Measured data is especially useful in modelling as well as analysing moisture damages.

Study on the breaking characteristics of glass-like brittle materials

Abstract In order to solve the problem of accumulation of glass waste seriously affecting people’s life safety, it is of great significance to study the crushing mechanism of glass waste. At present, no scholars have studied and analyzed the waste glass head, especially the single-axis compression test. In this study, a three-dimensional waste glass is established by discrete element software, and the single-axis compression characteristics of waste glass at different loading rates are analyzed by using Hertz contact model provided by the software. The results show that the loading rate is influenced by the equilibrium iteration rate and stress loading step length. The study also analyzes the pressure plate extruding waste glass in different positions. Finally, the stress–strain strength of five groups of waste glass under the action of uniaxial compression is analyzed, and the stress strength is between 0.3 and 0.56 MPa. This study provides a theoretical basis for further study of the breakage characteristics of waste glass under composite loading.

Influences of cement asphalt emulsified mortar construction on track slab geometry status

PurposeThe construction of cement asphalt (CA) emulsified mortar can obviously disturb the slab status after the fine adjustment. To decrease or eliminate the influence of CA mortar grouting on track slab geometry status, the effects of grouting funnel, slab pressing method, mortar expansion ratio, seepage ratio and grouting area on China Railway Track System Type (CRTS I) track slab geometry status were discussed in this paper.Design/methodology/approachCombined with engineering practice, this paper studied the expansion law of filling layer mortar, the liquid level height of the filling funnel, the pressure plate device and the amount of exudation water and systematically analyzed the influence of filling layer mortar construction on the state of track slab. Relevant precautions and countermeasures were put forward.FindingsThe results showed that the track slab floating values of four corners were different with the CA mortar grouting and the track slab corner near CA mortar grouting hole had the maximum floating values. The anti-floating effect of “7” shaped slab pressing device was more efficient than fixed-joint angle iron, and the slab floating value could be further decreased by increasing the amount of “7” shaped slab pressing devices. After CA mortar grouting, the track slab floating pattern had a close correlation with the expansion rate and water seepage rate of CA mortar over time and the expansion and water seepage rate of the mortar were faster when the temperature was high. Furthermore, the use of strip CA mortar filling under the rail bearing platform on both sides could effectively reduce the float under the track slab, and it could also save mortar consumption and reduce costs.Originality/valueThis study plays an important role in controlling the floating values, CA mortar dosage and the building cost of projects by grouting CA mortar at two flanks of filling space. The research results have guiding significance for the design and construction of China's CRTS I, CRTS II and CRTS III track slab.

Power System Relay Protection Based on Faster R-CNN Algorithm

The technology of relay protection in China's power system has gradually changed from the traditional operation mode to the development direction of informatization, intelligence, and automation. As a result, the role of relay protection in the power system has become more and more important. It brings higher requirements to the reliability of relay protection; effective reliability assessment of the relay protection system and the corresponding condition operation, minimize or avoid accidents, and ensure the safety of power grids. Starting from the operating characteristics of relay protection, it is suitable for practical engineering applications. Aiming at the problems of low work efficiency and low inspection quality in manual inspection of relay protection pressure plate switching state, The Faster R-CNN image processing algorithm will be come up with. This method uses grayscale, binarization and filtering techniques to preprocess the platen photos, and uses RPN.

Walking with individualized 3D-printed minimal footwear increases foot strength and produces subtle changes in unroll pattern

IntroductionThis 5-month follow-up study, involving 66 subjects (38 intervention, 28 control; 34 females, 32 males), evaluated the biomechanics of walking while wearing bespoke, 3D-printed footwear.MethodsA 3D scanner was used to obtain foot shape, which was subsequently modified to yield a suitable instep and additional room in the forefoot and toe areas, to allow for potential shape changes of the foot. Shoes were manufactured using TPU laser sintering. Pre (T0) and post (T1) the intervention, plantar pressures were collected using a plantar pressure plate (3 trials per foot) and toe flexor strength (5 trials per foot) was measured using a dynamometer, for control and intervention groups. Plantar pressure peak patterns and center-of-pressure (CoP) timing was analysed using 2D and 1D Statistical Parametric Mapping, respectively. Toe strength changes were expressed in percent and per individual as: 100 x ((strength@T1strength@T0) / strength@T0).ResultsPeak pressure distribution did not differ between control and intervention populations, or between T0 and T1. Center-of-pressure unroll differed between barefoot and shod conditions at T0 for the intervention group. When barefoot, the intervention group at T1 showed a more lateral CoP in early stance and a more anterior CoP in late stance compared to T0. In the intervention group, toe strength increased significantly by 48.5% between T0 and T1.DiscussionOverall, the results indicate that the bespoke, 3D-printed footwear did not significantly affect peak pressure distribution compared to barefoot walking. However, center-of-pressure patterns during gait were influenced, particularly in the intervention group, with analysis indicative of barefoot subjects' CoP moving faster in early and mid-stance than when shod. Additionally, the intervention led to a significant increase in toe strength. These findings contribute to our understanding of the biomechanical effects of customized 3D-printed footwear and highlight the potential benefits of such interventions in improving foot function and strength.

Effect of matrix suction on the shear strength characteristics of reinforced granite residual soil

Introduction: The soil in geogrid-reinforced structures is typically unsaturated, with the shear strength provided by both the matrix suction and the reinforced body. Traditional structural designs for saturated soils only consider the shear strength provided by the reinforced body, neglecting the part provided by matrix suction. As a result, the design for reinforced structures is biased toward conservatism.Method: The study examined the matrix suction-provided shear strength in reinforced soils through strain-controlled triaxial and soil-water characteristic curve (SWCC) pressure plate instrumentation. The feasibility of the Schrefler and Khalili unsaturated soil shear strength formulas for predicting shear strength based on matrix suction forces was verified.Results: The study revealed that the cohesion of saturated reinforced soil exhibits a significant decrease in contrast with unsaturated reinforced soil, with matrix suction serving as a crucial consideration for reinforced structure design.Discussion: The experimental results confirm the suitability of applying the quasi-cohesion increment theory to reinforced clays. The Khalili formula can be utilized to predict the quasi cohesion of unsaturated reinforced soils with greater accuracy under diverse dry density conditions. The results obtained using post-shear moisture content were closer to the measured values than those using initial moisture content.

An Experimental Investigation and Numerical Analysis of the Thermal Behavior of a Clutch System Using the Frictional Facing of Functionally Graded Materials

The friction clutch design strongly depends upon the frictional heat generated between contact surfaces during slipping at the beginning of the engagement. Firstly, the frictional heat generated reduces the performance of the clutch system and then leads to premature failure for contacting surfaces in some cases. The experimental effort in this work included manufacturing friction facing from functionally graded material (FGM) (aluminum and silicon carbide) for the clutch system. For this purpose, a special test rig was developed to investigate the thermal behavior of FGM and compare it with other frictional materials. The Taguchi L9 orthogonal design was selected to analyze the effect of the three factors (rotational, speed, torque, and the type of the frictional material) with three levels on the surface temperature of the contacting surfaces. A three-dimensional finite element model was built to validate the experimental results where the difference between them did not exceed 5.2%. The experimental results showed that the temperatures grew with the disc radius. Furthermore, the surfaces of the pressure plates and the flywheel were affected by frictional heat flow, and this effect increased when increasing the sliding speed. The lowest temperatures occurred when using FGM, which was lower than the other materials by 10%. This study presented an integrated approach consisting of design, manufacturing, and testing to study the complex frictional materials’ effect on the clutch system’s tribological performance.

A New Multi-Physics Coupled Method for the Temperature Field of Dry Clutch Assembly

The temperature field of the clutch assembly is critical for the clutch design and operation life. Current modeling methods of the temperature of the clutch assembly suffer from insufficient accuracy or a limited time scale for the complicated multi-physics coupling between the contact force, friction-generated heat, heat transfer, and thermal deformation in the clutch assembly in harsh operation conditions. In order to improve the accuracy of temperature field simulation and achieve long-term time scale, a new approach to modeling the temperature is proposed based on CFD simulation and decoupling technology. Firstly, the flow-thermal bi-directional coupling method is employed to determine the convective boundary conditions between the clutch assembly and the ambient air, improving the model’s accuracy. Secondly, the thermal-solid decoupling method is then used to reduce the computational time. The temperature of the clutch assembly during the continuous engagement and disengagement process is performed using this approach and verified by the rig test. The results demonstrate that the temperature of the outer, middle, and inner diameters of the pressure plate by the model agrees well with that by the rig test. For the first engagement and disengagement processes, the proportion of simulated temperature deviations exceeding 5 °C from the measured data is only 3.03%. For the last engagement and disengagement process, while the maximum temperature of the clutch is above 350 °C, the maximum temperature deviation between simulation and measurement is 4.99%. It proves that the approach proposed for modeling the dry clutch assembly temperature field has high accuracy while achieving long-term time-scale simulation.

Low-dose xenogeneic mesenchymal stem cells target canine osteoarthritis through systemic immunomodulation and homing

BackgroundAs current therapies for canine osteoarthritis (OA) provide mainly symptomatic improvement and fail to address the complex pathology of the disease, mesenchymal stem cells (MSCs) offer a promising biological approach to address both aspects of OA through their immunomodulatory properties.MethodsThis study aimed to investigate the safety and efficacy of xenogeneic MSCs in dogs with OA at different dose levels after intravenous injection. OA was surgically induced in the right stifle joint. Thirty-two male and female dogs were divided into three treatment groups and a control group. Regular general physical examinations; lameness, joint, radiographic, and animal caretaker assessments; pressure plate analyses; and blood analyses were performed over 42 days. At study end, joint tissues were evaluated regarding gross pathology, histopathology, and immunohistochemistry. In a follow-up study, the biodistribution of intravenously injected 99mTc-labeled equine peripheral blood-derived MSCs was evaluated over 24h in three dogs after the cruciate ligament section.ResultsThe dose determination study showed the systemic administration of ePB-MSCs in a canine OA model resulted in an analgesic, anti-inflammatory, and joint tissue protective effect associated with improved clinical signs and improved cartilage structure, as well as a good safety profile. Furthermore, a clear dose effect was found with 0.3 × 106 ePB-MSCs as the most effective dose. In addition, this treatment was demonstrated to home specifically towards the injury zone in a biodistribution study.ConclusionThis model-based study is the first to confirm the efficacy and safety of systemically administered xenogeneic MSCs in dogs with OA. The systemic administration of a low dose of xenogeneic MSCs could offer a widely accessible, safe, and efficacious treatment to address the complex pathology of canine OA and potentially slow down the disease progression by its joint tissue protective effect.

Well-trained Endurance Runners' Foot Contact Patterns: Barefoot vs. Shod Condition.

We aimed to investigate the initial foot contact and contact time in experienced endurance runners at individualized speeds, in running shoes and barefoot. Forty-eight participants (33.71±7.49 y, 70.94±8.65 kg, 175.07±7.03 cm, maximum aerobic speed 18.41±1.54 km.h-1) were distributed into three groups according to athletic performance: highly-trained runners, middle-trained runners, and control group. An incremental running test until exhaustion was performed for assessing maximum aerobic speed. After≥24 h of recovery participants randomly walked and ran, barefoot and in running shoes, over a pressure plate at ~4.7 km.h-1 and 85% of the maximum aerobic speed, respectively. They wore the same model of running shoes with homogeneous lacing pattern. A rearfoot strike was performed by 68.8% and 77.1% of participants when running barefoot and in running shoes, respectively. Considering the tendency to develop a rearfoot strike was lower in the barefoot condition, runners with higher performance may benefit from training in minimalist running shoes because their foot contact pattern could tend towards a non-rearfoot strike. Our results suggest that initial foot contact and contact time are related to running performance and may also be influenced by running shoes.

Water-retention behaviour and microscopic analysis of two biopolymer-improved sandy soils

Soil erosion in the Yellow River basin in China has seriously affected the stability of the foundations of civil engineering structures. Traditional treated materials used for preventing the soil erosion are often harmful to the environment. Biopolymers have been widely used for soil improvement because of their low cost, environmental friendliness, and feasible application. However, most studies on the water-retention behaviour of treated soils conducted to date have focused on the low or high suction range, while few have examined the behaviour over a wide suction range. Converting the saturated state of treated soils into unsaturated state until it is completely dry will lead to changes in the water retention behaviour of biopolymer-treated soils. Therefore, this study investigated variations in the water-retention behaviour and micromechanism of biopolymer-treated sandy soils over a wide range of suction. Specifically, the water-retention behaviour of treated soil was tested using a pressure plate apparatus in the low suction range and a WP4C apparatus in the high suction range. Scanning electron microscopy was also used to evaluate water-retention mechanism of soils treated with different ratios of biopolymer. Biopolymers were found to absorb water to form hydrogels and biofilms, which reduced the pore spaces between soil particles and improved the water storage ability of sandy soils. The water-retention capacity of both Xanthan gum and Gellan gum-treated sandy soils was higher than that of untreated sandy soils, and increased as the biopolymer ratio increased. The water-retention behaviour of the Gellan gum-treated sandy soil were better than that of the Xanthan gum-treated sandy soil. Finally, a prediction model of the soil–water retention curve that considered the biopolymer ratio was proposed based on the Fredlund-Xing model. This study provides a scientific basis for the application of biopolymers to control soil erosion in the Yellow River basin in China.

Study on temperature field and deformation field of AMT dry clutch assembly under continuous slip grinding

In this paper, Ansys finite element analysis was used to study the temperature and deformation fields of clutches after continuous slip grinding for the 30s, 45s, and 60s, under different constraints on the pressure plate, and after cooling to room temperature. Its sliding time is extended while cooling the clutch from the highest temperature to the initial temperature through a certain setting, and then its temperature field and deformation field are analyzed at different sliding times after cooling. Through this study, we can explore the performance of this clutch under extremely harsh working conditions, to analyze whether it meets the standard of use of the corresponding car or makes corresponding optimization improvements.As the sliding time increases, the maximum temperature of the clutch rises, and the temperature is transmitted to the inner and outer diameters centered on the sliding surface. As the temperature generated by continuous sliding grinding continues to rise, the deformation of the clutch assembly also increases, and when the temperature drops, the clutch will quickly reduce a certain amount of deformation in a short period and then gradually return to its original shape. The higher the temperature, the more likely the clutch is to deform. When the temperature is at a lower value, its ability to deform and its rebound performance will also decrease.

Effect of soil hydrophobicity on soil-water retention curve of a silt loam soil

Soil wettability is an important property that affects the behaviour of fine-grained soils. Previous studies have shown that hydrophobicity induced by organic or silane additives may affect the soil-water retention curve (SWRC). However, current findings regarding the effect of hydrophobicity on the SWRC are controversial. Previously, organic or silane additives were assumed to change only the soil wettability. Nevertheless, this study shows that polyvinyl alcohol (PVA) can change the hydrophobicity, pore size distribution (PSD), and specific surface area (SSA) of soil, thus affecting the SWRC. PVA-treated soil is hydrophobic when cured at 20 ℃, but hydrophilic when cured at 100 ℃. No thermal degradation is indicated in the PVA at 100 ℃ based on thermogravimetric analysis and a comparison of mass loss, and the sole difference between the PVA-treated soils cured at 20 and 100 ℃ is their wettability. This study managed to make the hydrophobicity caused by PVA to become an independent variable separated from the PSD and SSA by controlling the ambient temperature. The wetting and drying curves are measured under isopiestic humidity control in the high-suction domain (2.7–298.7 MPa), whereas pressure plates are used for the drying curves in the low-suction domain (0–800 kPa). The results obtained indicate that soil hydrophobicity significantly accelerates drainage when the matric suction is between 100 and 400 kPa, and an increase in PVA content increases the water retention capacity of soil. When the matric suction exceeds 2.7 MPa, the effect of soil hydrophobicity on the SWRC of the soil weakens. At this time, the SWRC is dominated by the van der Waals force, and the SSA contributes significantly to the process. Additionally, this study enables some controversial findings from previous studies to be explained, which is of great significance in soil and agriculture sciences.