Deep Displacement Research Articles

The Effects of Active Range of Motion on Upper Trapezius’ Fasciae Displacement among Individuals with and without Myofascial Pain Syndrome

Aim: This study determined the differences in upper trapezius' superficial and deep fascia slides among MPS and non-MPS participants after performing cervical active range of motion (AROM). The association between the fascia slides, age, sex, occupation, clinical diagnosis, and symptoms’ chronicity were determined. Methods: This retrospective study constituted a reliability and case-control study. Three hundred participants (174 MPS: 126 non-MPS) were included. For each fascia level, six physiotherapy interns read 19 MSUS videos. Bland Altman Plot and Single Measures Intraclass Correlation Coefficient (ICC) determined the physiotherapy interns' intratester and intertester reliability. Twelve physiotherapy interns quantified the fascia slides in 3,600 MSUS videos. MPS and non-MPS groups were compared against differences in fascia slides using independent samples t-test. A p-value of <0.05 indicated significant differences in fascia slides. Multiple regression analyses determined fascia slides and independent variables’ relationship. Results: Intertester reliability in tracking the superficial and deep fasciae was very good (ICC = 0.90 to 1.00). Intratester reliability showed minimal to no individual bias (95% CI). A significant difference in superficial fascia displacement between groups was only observed during active cervical extension (p< 0.05). No difference in cervical AROM was reported in deep fascia displacement between groups (p> 0.05). No associations were found between superficial fascia slides and independent variables (p >0.05). Sex was the only variable associated with deep fascia slide difference (p <0.05). Conclusion and Implications: Limited fascia slide is not a characteristic of individuals with MPS. There is no association between differences in fascia slides and independent variables.

Centrifugal model test on a riverine landslide in the Three Gorges Reservoir induced by rainfall and water level fluctuation

Frequent soil landslide events are recorded in the Three Gorges Reservoir area, China, making it necessary to investigate the failure mode of such riverside landslides. Geotechnical centrifugal test is considered to be the most realistic laboratory model, which can reconstruct the required geo-stress. In this study, the Liangshuijing landslide in the Three Gorgers Reservoir area is selected for a scaled centrifugal model experiment, and a water pump system is employed to retain the rainfall condition. Using the techniques of digital photography and pore water pressure transducers, water level fluctuation is controlled, and multi-physical data are thus obtained, including the pore water pressure, earth pressure, surface displacement and deep displacement. The analysis results indicate that: Three stages were set in the test (waterflooding stage, rainfall stage and drainage stage). Seven transverse cracks with wide of 1–5 mm appeared during the model test, of which 3 cracks at the toe landslide were caused by reservoir water fluctuation, and the cracks at the middle and rear part were caused by rainfall. During rainfall process, the maximum displacement of landslide model reaches 3 cm. And the maximum deformation of the model exceeds 12 cm at the drainage stage. The failure process of the slope model can be divided into four stages: microcracks appearance and propagation stage, thrust-type failure stage, retrogressive failure stage, and holistic failure stage. When the thrust-type zone caused by rainfall was connected or even overlapped with the retrogressive failure zone caused by the drainage, the landslide would start, which displayed a typical composite failure pattern. The failure mode and deformation mechanism under the coupling actions of water level fluctuation and rainfall are revealed in the model test, which could appropriately guide for the analysis and evaluation of riverside landslides.

Coherent Lagrangian Pathways Near an East Alboran Front

AbstractIn the eastern Alboran Sea, frontogenesis (FG) is a dominant process for fronts extending from the Spanish coast toward the basin interior, promoting large vertical displacements that connect the surface mixed layer with the oceanic interior. Using a realistic, high‐resolution model simulation for this region, we conduct the offline advection of virtual water parcels released near the surface during a 2‐day episode of intense FG. Three‐dimensional trajectories exhibit high variability depending on the release location, and some large, rapid vertical displacements are induced by different coherent submesoscale flow patterns and by interactions among them: Ageostrophic secondary circulation associated with strain‐ and mixing‐induced FG and internal waves generated by currents over topography. These deep displacements mostly are irreversible, at least on a short time scale, because of the rapidly changing flow patterns. Significant diapycnal mixing and density changes occur along trajectories as they pass through the surface and bottom boundary layers. While we expect these processes to be typical for this region, the computational expense of such a Lagrangian analysis and the complexity of its outcome present a considerable challenge for more comprehensive assessments.

Force and deformation response analysis of dual structure slope excavation and support

Aiming at the problem of fuzzy selection basis of dual-structure slope simulation calculation parameters and the complicated force and deformation of the slope body in the supporting process. The study relies on the treatment project of the right side slope of the K5 + 220-K5 + 770 section of the TJ1A section of the Jiangwen Expressway. The slope is a gravel soil-weathered bedrock dual structure slope, which is referred to as Hetangba slope in the study. Use Midas/GTS NX to build a trial calculation model. A new method for checking simulation parameters of deep displacement monitoring data is proposed. The superposition calculation method of pore water pressure is proposed to realize the slope stress-seepage coupling. The analysis method of slope excavation and support process is put forward. The analysis shows that the most dangerous working condition in the slope excavation and support process is the second-level excavation. When there is a local displacement and plastic strain concentration area on the slope, the reference significance of the extreme value and the safety factor is reduced. Compared with the application of pore water pressure and no pore water pressure, there is no obvious change in the position of the extreme value of horizontal displacement and plastic strain in working conditions 2–8, but the extreme value changes are different. The slope safety factor of working conditions 2–8 is reduced. The continuous distribution zone of plastic strain inside the slope disappeared in condition 7. There is a very small unstable area on the top of the third-level slope of working conditions 9–11. The research results have great theoretical guiding significance for the measurement and control simulation and early warning analysis of the dual structure slope construction process.

Identification of a locking segment in a high-locality landslide in Shidaguan, Southwest China

Identification of a locking segment is crucial to assess the potential runout risk and the overall stability of a high-locality landslide. However, it is difficult to identify a locking segment through field surveys before a landslide failure due to their concealment. Taking the Tizicao landslide—a high-locality landslide in Southwest China—as a field example, this study aims to identify and analyze a locking segment of the landslide. Based on geomorphology and spatial–temporal deformation of the landslide, the characteristics for identifying the locking segment of the Tizicao landslide are analyzed, and the locations and area of the locking segment are determined based on the analytical results. Furthermore, the identification results are interpreted through fieldwork including the displacement monitoring of ground surface and deep parts, borehole drilling, and oblique photography using unmanned aerial vehicles. The results reveal that the locking segment of the Tizicao landslide lies at the southern slope toe and covers an area of approximately 4.69 × 104 m2, accounting for 15.2% of the total area of the landslide. Significantly different characteristics are observed in respect of surface displacement, deep displacement, surface cracks, and sliding zone soil between locking and non-locking segment.

Numerical Simulation of Coupling Support for High‐Stress Fractured Soft Rock Roadway in Deep Mine

Aiming at the difficulties during the support of high‐stress fractured soft rock roadway in deep mine, a comprehensive surrounding rock management method of bolt‐net‐cable‐grout coupling support is proposed and the mechanism of interaction between coupling support and surrounding rock is analyzed by numerical simulation. The effectiveness of the coupling support is proved by an application in the east wing return‐air roadway in the Qingdong Coal Mine of Huaibei Mining Group. The results show that the surrounding rock plastic zone near the sidewall and floor of high‐stress fractured soft rock roadway is larger than that near the roadway roof, and its distribution range can be reduced by using the coupling support. And, the coupling support can improve the reliability of roadway support and the stability of surrounding rock by reducing the axial stress of anchor bolts, the stress concentration of surrounding rock caused by anchor bolt, the roadway surface displacement, and deep displacement of surrounding rock.

Emergency Survey and Stability Analysis of a Rainfall-Induced Soil-Rock Mixture Landslide at Chongqing City, China

The stability analysis of damaged landslides and unstable debris is important for rescue work and emergency operations. This paper investigates a predisposed geological emergence, inducing the factors and deformation processes of the Zhongbao landslide, which happened on July 25, 2020. The stability of the landslide debris was evaluated by an integrated monitoring system consisting of ground-based radar, unmanned aerial vehicles, airborne Lidar, thermal infrared temperature monitoring, GNSS displacement monitoring, deep displacement monitoring, and rainfall monitoring. The strata and weak layer controlled the landslide failure, and topography defined the boundary of the failed rock mass. A continually intensive rainfall caused the deformation and accelerated failure of the landslide. The shallow and steep deposit (Part I) firstly slid at a high velocity, and then pushed the rear part of the landslide (Part II) to deform, forming numerous cracks, which accelerated the rainfall infiltrating into the rock mass. The moisture content increase could decrease the strength of the shale rock within the bedding planes. Finally, with the rock and soil mass sliding along the weak layer, a barrier dam and a barrier lake were formed. The monitoring and numerical simulation results showed that after the landslide failure, there was still local collapse and deformation occurrences which threatened rescue work and barrier lake excavation, and the stability of the accumulation area gradually decreased as the rainfall increased. Therefore, the barrier dam was not excavated until the accumulation rate gradually stabilized on July 28. Moreover, most of the reactivated deposits still accumulated in the transportation and source areas. Thus, in August, the displacement of the landslide debris gradually accelerated in a stepwise manner, and responded strongly to rainfall, especially in the accumulation area, so that it was inferred that the damaged landslide could slide again and cause a more threatening and severe failure. The analysis results of the study area can provide references for the failure mechanism of a rainfall-induced landslide and the stability evaluation of a damaged landslide.

Early Warning Indicators of Landslides Based on Deep Displacements: Applications on Jinping Landslide and Wendong Landslide, China

Real-time monitoring and early warning have great significance in reducing/avoiding the consequences caused by landslides. The deep displacement-based monitoring method has been proven to be a suitable solution for landslide risk management. However, the early warning indicators based on the deep displacement method need to be fully understood. This paper reports on an investigation into early warning indicators and deformation monitoring of several natural landslides. A series of indicators using the profiles of the accumulative displacement, kinetic energy, and their rates against time for early warning are developed and calibrated by monitoring and analyzing a natural landslide. The early warning indicators are then applied to monitor and identify the different deformation stages of the Jinping County North Landslide and the Wendong Town Landslide.

Real-time and Multi-physics Fiber Optic Monitoring of Landslides in Three Gorges Reservoir Area

Accurate and real-time measurement of the evolution of landslides has become a great concern in recent years. Fiber Bragg grating (FBG), as a popular quasi-distributed fiber optic sensing technology, has been successfully applied to geotechnical and geohazard monitoring. In this paper, an FBG-based real-time monitoring system has been developed to capture the multi-physics evolution of creeping landslides. The system was employed to monitor the performance of the Majiagou and Xinpu landslides in the Three Gorges Reservoir (TGR) area of China, respectively. The results show that the FBG monitoring system can accurately obtain the variations of ground temperature, soil moisture, and deep displacements, which provides valuable information for evaluating the landslide deformation and failure mechanisms during the operation of the reservoir. In this way, real-time stability analysis and early warning can be achieved.

Deep displacement monitoring and foundation base boundary reconstruction analysis of diaphragm wall based on ultra-weak FBG

The instability or destruction of diaphragm walls in underground engineering will cause significant economic losses and casualties. The distributed and high-precision monitoring of diaphragm wall deformation can provide reliable and detail data for disaster early-warning as well as economical design. However, recording continuous deformation of the diaphragm wall using traditional monitoring technologies remain challenging. Moreover, the basement movement of diaphragm wall is rarely considered in previous studies. In order to overcome the shortcomings of the current displacement monitoring methods and deal with the basement boundary issues, a new base boundary reconstruction (BR) was proposed and the ultra-weak Fiber Bragg grating (UWFBG) technology was adopted to monitor the displacement of the diaphragm wall. For validation, a laboratory test based on ultra-weak FBG was carried out and the feasibility of the BR method was demonstrated. Subsequently, the ultra-weak FBG and the BR method were applied to Shanghai metro line 18. The results showed that the monitoring technology and analysis method proposed in this paper can obtain detailed deformation information of the diaphragm wall in real-time, which not only provides an advanced monitoring method for the deep deformation of diaphragm wall, but also solves the deformation calculation issue with the base boundary condition changes involved.

The Relationship between Mining-Induced Stress and Coal Gas under an Optimized Support Scheme: A Case Study in the Guanyinshan Coal Mine, China

Stress is one of the main factors influencing coal and gas outbursts. The apparent effects of the crustal stress, the structural stress, and the mining-induced stress increase as the depth of mining increases. At present, there have been few studies of the relationship between the comprehensive analyses of the crustal stress, mining-induced stress, and coal gas. The in situ measurement of the relationship between stress-related behaviors and coal gas under the influence of mining was conducted through experimental analysis of surrounding rock support and coal and gas outburst control and optimization of surrounding rock support materials and system construction. The results showed that the mining-induced stress first increased to a peak value, then gradually decreased, and tended to stabilize as the footage progresses. Stress appears at 96 m ahead due to mining; after 57 m of advancing, there is a large increase until it passes through this area. The stress in front of the working face increases linearly, and the increase range is obviously larger than that of the coal body in a certain range on both sides. The support anchoring force gradually decreased and tended to be stable after rapidly increasing to a maximum value. The deep displacement of the roof increased linearly and tended to be stable after reaching an accumulated displacement which can reach 16-28 mm. The residual gas pressure in front of mining operations decreased rapidly, and beyond 15 m on each side of the roadway, it decreased significantly. The residual gas pressure and gas content were consistent with the gas desorption index of drill cuttings due to the influences of gas predrainage and mining. The stress along the direction of the roadway and the residual gas content, the residual gas pressure, and the gas desorption index of drill cuttings conform to the logarithmic functional relationship. The research results provide a basis for the comprehensive prevention and control of coal and gas outbursts from multiple angles considering stress, coal, and gas.

DEFORMATION CHARACTERISTICS AND INSTABILITY MECHANISM OF LARGE MONOCLINAL LAYERED NEOGENIC BEDROCK LANDSLIDE IN THREE GORGES RESERVOIR AREA

This paper take the Jiaodingfeng Ⅱ landslide in Wushan County of the Three Gorges Reservoir area as an example and combines the reservoir water level changes and geological environment conditions data. It analyzes the deformation characteristics,formation mechanism and development trend of the landslide in detail. It uses field survey and mapping,UAV,engineering geological drilling,surface and deep displacement monitoring and other techniques. The volume of the landslide is about 250×104 m3. It is a large monoclinal neogenic bedrock landslide. The height difference between the front and rear edges of the landslide is about 380 m. The leading-edge shear outlet is high and steep and is located below the reservoir water level. The deep monitoring data show that there are two sliding zone in the water-level-fluctuation zone. The two zones are located between 12.0~17.0 m and 25.0~30.0 m from the slope. At present,the landslide is in the creep deformation stage. Under the influence of landform,stratigraphic structure,deterioration of the water-fluctuation zone and water,the vertical displacement continues to increase. The front deterioration zone has a high possibility of sliding failure and instability,and there is a risk of landslide surge disaster chain. It is suggested to carry out continuous observation and research on the deterioration system of the fluctuation zone in the reservoir area to improve the ability of identification and early warning of new landslide disasters in the reservoir area.

Development of a novel Hall element inclinometer for slope displacement monitoring

Deep displacement monitoring of slopes is one of the most effective means for early warning, and it is of considerable significance for preventing landslide disasters. This paper introduces a novel inclinometer based on the Hall element sensor to monitor slope displacement. The Hall sensor units are connected in an array to form the inclinometer, which can realize deep-seated slope deformation monitoring. Furthermore, calibration, validation, and slope model experiments were carried out. The research shows that the Hall element can effectively sense magnetic flux density. Compared with other inclinometers, the novel inclinometer can achieve non-contact measurement with a large angle measuring range of −45° to 45° The measuring precision is 1% F.S. The performance of the inclinometer is stable and the maximum error of measurement is within −2.46 to 2.34 mm/m, which can meet the requirements of geotechnical engineering. So, the Hall element inclinometer is reliable for slope displacement monitoring.

Mechanism analysis and partition characteristics of a recent highway landslide in Southwest China based on a 3D multi-point deformation monitoring system

An increasing number of landslides are occurring during the construction of highways in mountainous areas all over the world. A recent highway landslide located in the mountainous region of Southwest China is taken as a representative example to carry out the initiation mechanism and deformation characteristics analysis, and study the intelligent partitioning method in this paper. The geological conditions of the landslide are obtained through detailed geological surveys and investigation. A three-dimensional (3D) monitoring network with a total of 72 multi-points, including 53 surface displacement monitoring points and 19 deep displacement monitoring holes, is established to examine the spatial deformation characteristics of the landslide for nearly 25 months. The monitoring results of the surface displacement show that the dynamic deformation of the landslide can be divided into three stages, namely initial deformation stage, accelerated deformation stage, and stabilization stage. Based on the strata distribution obtained by the borehole investigation and the results of deep displacement monitoring, the depth of the slip surface can be reliably determined. The smart contract method in blockchain technology combined with the multi-point monitoring dataset is novelty applied to realize the intelligent automatic partition of the highway landslide without any human involvement. This method can provide the basis for further independent analysis of different landslide zones. According to the investigation and analysis, the initiation mechanism for the highway landslides is attributed to both internal poor geological conditions and external intense precipitation and engineering excavation.

Study on the interaction mechanism between deep displacement of soil and internal force of anchor cable under pile-anchor support system of ultra-deep foundation pit

Based on a concrete engineering example, the change law of soil deep displacement and internal force of anchor cable in the excavation process of foundation pit under pile and anchor support system is simulated by numerical analysis method, and compared with the measured results, and the synergistic action law of soil deep displacement and internal force of anchor cable is discussed. The comparison between the results of finite element numerical analysis and the field measurement shows that the two-dimensional finite element numerical analysis can reflect the variation law of the deep displacement of soil and the internal force of anchor cable in the field to some extent.

Deformation Characteristics of Tianjiaba Landslide Induced by Surcharge

The Tianjiaba landslide on the Hang Rui expressway was located in the south of Sinan County, Tongren City, Guizhou Province. From the night of 2 July to the morning of 3 July 2011, numerous house cracks, foundation subsidence, and surface cracks suddenly occurred in the Tudiwan and Tianjiaba villages on the north and south sides of the management area. Based on the field geological survey, drilling, pit exploration, surface displacement, fracture observation, and deep displacement monitoring data analysis the deformation characteristics and causes of the Tianjiaba landslide were comprehensively analyzed. In this study, the landslide was divided into three areas, in which fracture group 3 was the most severe. Among the ten inclinometer holes, the sliding surface displacement of No.8 inclinometer hole was the largest, i.e., 25 mm. The sliding surface slopes of fracture groups 1, 2, and 3 were small, i.e., 12.25°, 4.97° and 6.62° to 4.64°, respectively. The results showed that the displacement values of different positions of the landslide were different, and the ground displacement value was larger than the sliding surface displacement value. The maximum displacement of the ground was 242.68 mm, which is larger than the maximum displacement of the inclinometer hole. Because the displacement of the upper part was greater than that of the lower part, bulging cracks formed in the lower part of the landslide. When the displacement of the upper part was less than that of the lower part, tension cracks formed in the lower part of the landslide. According to the surface cracks and displacement values of inclinometer holes on the sliding surface, the landslide was in the initial sliding stage and filling the platform of the management area on the hillside was the main cause of the landslide.

Causes and treatment measures for deformation of retaining soil and slope

To explore reasons for deformation of retaining soil and slope in the Maternal-Child Health Care Hospital of Hanyuan County, the meteorology, geological lithology, geological structure, and hydrological conditions were surveyed. Moreover, types and distributions of weak intercalated layers were found out by drilling, and physical and mechanical properties were obtained through physical mechanics and field shear test. Meanwhile, by means of drilling and monitoring, deformation range and characteristics of retaining soil and slope were determined, and deformation mechanism was obtained through monitoring crack opening and deep displacement. The structures showed that deformation occurred at new 2# counterweight retaining wall is caused by shallow slip control surface RJ0; the pulling and crack of settlement joints between the new 2# counterweight retaining wall and the new 1# slab-pile wall are caused by the deformation of shallow slip control surface RJ0; the deformation and failure of new 2# counterweight retaining wall and new 1# slab-pile wall and their foundation rock mass at the lower part are caused by creep displacement of “shallow weak intercalated layers” RJ0 and RJ1; in addition, the deep creep control surface RJ2 has certain influence on the deformation of upper building and its foundation rock mass. Therefore, anti-slide piles should be used to control the shallow slipping control surface RJ1, with the depth reaching the structural plane where the deep creep control surface RJ2 is located.

Design and Test of a MEMS Accelerometer Array for Submarine Landslide Displacement Monitoring

AbstractSubmarine landslides in gas hydrate areas are a significant geo-hazard that can cause considerable damage. The processes and mechanism of submarine landslides caused by gas hydrate dissociation are not clearly understood. Therefore, we designed a micro-electro-mechanical systems (MEMS) accelerometer array to study and monitor the deep displacement of submarine landslides. The MEMS accelerometer array consists of several gravity acceleration-sensing units that are protected and positioned using a flexible circuit board and elastic steel tape, such that all the units are connected to an Inter-Integrated Circuit (IIC) communication bus. By sensing the three-axis tilt angles, the direction and magnitude of the displacement for a measurement unit can be calculated; then, the overall displacement of the array is calculated as the difference in the displacements from the initial values. To ensure the accuracy of the tilt angle and displacement calculation, the calibration and verification test of the single MEMS sensor and sensor array is conducted. The MEMS accelerometer array is verified with respect to its principle and arrangement by a laboratory physical model test, and the initial experimentation demonstrated the capacities of the monitoring system for collecting real-time and in-situ information about the dynamic process and propagation of slope failure.

Prediction of landslide sharp increase displacement by SVM with considering hysteresis of groundwater change

The displacement-time curves of reservoir landslide mostly show step-by-step growth characteristics. The sharp increase of the displacement plays a significant role in the evolution process of the step-like landslide, so it is extremely important to accurately predict the suddenly change displacement of landslide. In order to overcome the shortcomings existed in the current displacement monitoring methods and prediction models for the mutation displacement of landslide, this paper proposed a hybrid machine learning displacement prediction model based on Support Vector Machine, including Support Vector Classification(SVC) and Support Vector Regression(SVR), optimized by Particle Swarm Optimization (SVC-PSO-SVR) and considering the hysteresis of groundwater level change. The Majiagou No. 1 Landslide in the Three Gorges Reservoir (TGR) Area, whose deformation shows typical step-by-step tendency, was illustrated. Base on the deep displacement data of Majiagou landslide from January 2016 to December 2017, the landslide deformation pattern can be divided into two states: stability and acceleration. Firstly, the SVC model was adopted to predict the time range of acceleration state. Then, considering the lag fluctuation of groundwater level, the concept of “equivalent reservoir level” was proposed. Finally, based on SVC model, the sharp increase displacement of landslide was predicted using PSO-SVR model. The proposed SVC-PSO-SVR model yielded the root mean square error (RMSE) of 0.08827 mm and the mean absolute percentage error (MAPE) of 0.02105 mm. Besides, the prediction accuracy of SVC can attain 96.49% (55 / 57). The results show that the model can accurately predict the time range and displacement of acceleration deformation section of Majiagou landslide. The proposed model is of great significance for landslide prediction and early warning.

Critical Ultimate Load and Ultimate Bearing Failure of CT110 with Initial Crack Defect

CT110 is ultra-high-strength coiled tubing (CT). It has been applied in the drilling, completion, fracturing and stimulation process of deep wells, ultra-deep wells and large displacement horizontal wells. Under complex load, the CT will crack and eventually failure. Fracture toughness of CT materials can be measured using Crack Tip Opening Displacement (CTOD). In this paper, a three-point bending finite element model (FEM) of CT110 material was established, and its critical CTOD value is obtained by calculation as 0.732 mm. The FEM of three-dimensional CT with initial crack was established and its feasibility was verified. The ultimate bearing failure analysis of CT with initial crack defects shows that under the same working condition, internal pressure accelerates the crack initiation and propagation speed, so that the crack of tubing body reaches the critical value in advance, and the maximum value at 130 MPa is close to the critical value. Under the combined loads, the maximum CTOD value of the CT with a crack increases with the increase in the crack depth and length, and the deeper the crack depth, the greater the influence of the crack length on its maximum value. This study on crack initiation and propagation of CT with defects provides a basis for predicting the fatigue life and revealing the failure mechanism of CT.