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To avoid engineering challenges during roadway excavation or workface mining in weakly cemented soft rock, the characteristics of this rock under the influence of associated stress paths must be explored. Therefore, this study investigates the principal strain and generalized shear strain of weakly cemented soft rock under a directional shear stress path, through a series of principal-stress directional shear tests conducted using a hollow cylinder apparatus. The damage morphology characteristics for different major principal-stress directions are also discussed. The results show that the major principal strain (ɛ1) gradually increased with increasing major principal-stress direction angle (α), when α ranges from 0° to 45°, whereas the minor principal strain (ɛ3) and intermediate principal strain (ɛ2) gradually decreased. The peak stress of the soft rock gradually decreased and a main slip-damage crack developed in the major principal-stress direction. The peak generalized shear strain increased slowly in the first compression–torsion stage and rapidly in the second. As α ranges from 45° to 90°, ɛ1 and ɛ2 decreased gradually whereas ɛ3 increased gradually. The peak stress also increased slowly, with the main crack developing in the minor principal-stress direction. Additionally, the peak generalized shear strain rapidly decreased in the first tension–torsion stage and then slowly decreased in the second. The principal-stress rotation space transformation matrix was introduced to modify the Lade–Duncan (L-D) criterion, and the criterion reliability was verified using the peak value of the soft rock deviatoric stress under different principal-stress directions. The modified L-D criterion considered the effects of both the principal-stress magnitude and direction. The results are of great significance for studying the influence of principal-stress direction and provide an important method to investigate the mechanical properties of rocks with complex stress paths comprehensively. [ABSTRACT FROM AUTHOR]

To validate the feasibility of the microseismic monitoring in the early warning of rockburst in TBM excavation engineering, and to study the rockburst characteristics of surrounding rock, a newly developed microseismic(MS) monitoring system was employed in the Tianshan-Shengli tunnel to detect MS activities, and then to predict and warn the rockburst disasters. The system not only has the advantages of accuracy of artificial analysis, but also has the real-time analysis and early warning function of cloud service platform, of which positioning accuracy for MS events is about 5-10 m. The prediction criterion of rockburst risk level adopted multiple evaluation indexes such as energy, moment magnitude and quantity of MS events. It reveals that the evolution of maximum energy has a good positive correlation with that of maximum moment magnitude, through analyzing the monitored MS events. According to the field statistical results of rockburst information, the rockburst generally occurs two days after the rockmass is exposed from the tunnel boring machine (TBM) tail shield, which belongs to the delayed rockburst. The preliminary application cases indicate that the rockburst prediction and early warning based on MS monitoring can serve the safety construction of TBM excavation project well. [ABSTRACT FROM AUTHOR]

Aiming at the condition of shield tunnel undercrossing the foundation of a pile group directly, using the settlement and inclination of the pile caps as the evaluation index, the reinforcing effect of the pregrouting of the soil around the pile foundation, the deep hole grouting behind the tunnel segment, and the combination of the two reinforcement methods are analyzed through three-dimensional numerical simulation. A reasonable reinforcement scheme is found and applied to practical engineering. The results show that for the pregrouting reinforcement of the soil around the pile, the optimal reinforcement scheme is to extend 0.5 m around the pile cap in the plane and vertically from the surroundings of the pile cap to 1/3 of the pile length below the bottom of the cap. When deep hole grouting reinforcement is adopted, larger reinforcement range and a certain range of radial reinforcement radius of tunnel section will result in a better effect of reinforcement. The combination of the two schemes is better than the single use of one. The practical application results show that the combined reinforcement scheme can effectively control the influence of shield tunnel excavation on the pile foundation of an elevated waiting hall. [ABSTRACT FROM AUTHOR]

With the continuous development of the geological engineering field, high-voltage electric pulse plasma rock-fracturing technology has become a research hotspot in recent years. It is now widely recognized that this fracturing technology has many application prospects and great economic benefits. Through the research process of this technology, it has proven to be an efficient and new type of rock-fracturing technology, which overcomes the problems of high cost, low efficiency, high safety risk, and serious pollution associated with traditional rock-fracturing technology. Also, it has unique advantages in terms of protecting the environment and reducing damage to the surrounding buildings. This paper reviews the research history of plasma shock wave influencing factors and pulsed discharge plasma rock-fracturing technology, summarizes the research on this technology from the perspectives of the mechanism of high-voltage electric pulse plasma rock fracturing and practical application, and discusses the feasibility of this technology when applied to the field of tunnel boring as well as the future development direction. This technology can be better used in the tunnel-boring field, which can greatly improve the tunnel-boring efficiency, but at present, the research on plasma rock-fracturing-assisted tunnel boring is still in the laboratory research stage, which lacks systematic research equipment and judging indexes, and the follow-up should focus on improving the systematic research capabilities of the plasma rock-fracturing-assisted tunnel-boring equipment, and systematically and comprehensively carry out research on rock-fracturing by plasma-assisted excavation equipment. [ABSTRACT FROM AUTHOR]

With the continuous development of dredging engineering and dredging business, the requirements for monitoring the dredging construction process are also increasing. Aiming at the problems of poor display effect and low accuracy in 3D visualization monitoring during the dredging process of existing dredgers, a universal 3D visualization system for dredger construction operations was designed and developed based on the Unity3D engine. The system realizes the 3D visualization display of key dredging equipment driving, underwater terrain generation and rendering, and real-time terrain reconstruction. Through actual dredger application verification, the system can effectively improve construction efficiency and quality, enhance construction accuracy, reduce the occurrence of missed excavation and over excavation, and has important engineering application value. [ABSTRACT FROM AUTHOR]

Fault rockburst warning has always been challenging in deep tunnel engineering, and there is no quantitative warning method for deep tunnel boring machine (TBM) tunnels. This study clarified the geological characteristics and microseismic (MS) activity characteristics of fault rockbursts, and a quantitative warning method that integrates geological information and MS information was established. The results of this study show that fault rockbursts are prone to occur near faults without filling or with hard filling, where the faults run through the tunnel, and where the orientation of the fault is at a small angle to the direction of the maximum principal stress. Fault rockbursts exhibit significant precursor characteristics during the development process, that is, MS events are characterized by a significant distribution along faults, a cumulative apparent volume growth rate of adjacent MS events greater than 45%, and an overall rising trend in the ratio of cumulative apparent stress to cumulative dynamic stress drop (K value), which can be used to identify whether a potential rockburst will be a fault rockburst. To further predict fault rockbursts, seven MS parameters were comprehensively used, including the intraday and cumulative number of MS events, intraday and cumulative MS release energy, intraday and cumulative MS apparent volumes, and K value. Based on the CRITIC method for determining weight coefficients, a quantitative fault rockburst warning method was established and successfully applied to a deep TBM tunnel. This method achieves dynamic warning of type identification, intensity, and probabilities of fault rockbursts during the excavation process of deep TBM tunnels. Highlights Fault rockbursts are prone to occur near faults without filling or with hard filling, where the faults run through the tunnel, and that the fault orientation is at a small angle to the maximum principal stress. Fault rockbursts have significant precursor characteristics: MS events are characterized by a significant distribution along the faults, a cumulative apparent volume growth rate (CAVG) of adjacent MS events greater than 45%, and an overall rising trend in the ratio of cumulative apparent stress to cumulative dynamic stress drop (K value). The K value can be used to differentiate the intensities of rockbursts on the basis of characterizing the development process of fault rockburst. A quantitative fault rockburst warning method for deep TBM tunnels was established, which achieves dynamic warning of type identification, intensity, and probabilities of fault rockbursts during the excavation process of deep TBM tunnels. [ABSTRACT FROM AUTHOR]

The presence of convex corners will affect the earth pressure calculation, but there is a paucity of studies on calculating the ground pressure of convex corners in excavation engineering. To address this issue, equilateral convex corners are divided into two types according to the relative relationship between the side length size of equilateral convex corners and the excavation depth, and their respective earth pressure calculation model is established. The microelement static equilibrium equation is set by the horizontal layer analysis method, and then the equations for calculating active earth pressure strength, active earth pressure, and active earth pressure acting points on the equilateral convex corners are derived. The example analysis and comparative Plaxis three-dimensional (3D) finite-element verification show that the friction angle in the soil is an important factor in distinguishing between two kinds of equilateral convex corners, and the active earth pressure strength, the active earth pressure, and the acting point will be affected by the side length and rotation angle, where the influence of the side length on the active earth pressure strength is relatively small. The active earth pressure may show a variety of different variation laws affected by soil parameters. The acting point will move in both directions of the plane with the change of side length and rotation angle. The theoretical calculations of active earth pressure agree with the results of three-dimensional simulations, which may explain the rationality and practicality of the theoretical method in this paper. [ABSTRACT FROM AUTHOR]

Excavator–truck operations, characterized by their repetitive excavation and loading tasks, present a prime candidate for automation. While numerous studies have aimed to automate the earthworks, practical implementations remain scarce. This research introduces a task component design focused on excavator–truck operation planning to improve the functionality of an earthwork automation system. To address this, fundamental task primitives necessary for executing excavation tasks were engineered, and a web-based system was developed to automate the generation of work plans for both point and trench excavation through algorithmic processes. Additionally, a JSON-based protocol was introduced to facilitate efficient integration with other subsystems. Field tests were conducted to validate the effectiveness of the newly developed algorithm and protocol within the broader context of earthwork automation systems. The results demonstrated the successful implementation of the task components, confirming their operational viability and seamless integration into the existing earthwork automation framework. [ABSTRACT FROM AUTHOR]

Underground engineering has led to the rapid development of tunnel boring machines (TBM), which have been used in practical projects such as transportation, municipalities, water, and electricity in recent years due to advantages such as excavation speed. Excavation speed, high safety, and good construction quality greatly affect the life of the hobs (disc cutters of TBMs). The rock-breaking process for rock crushing under the forces of TBM hobs was numerically performed using LS-DYNA software based on the finite element method. A full-section model with five hobs was used to simulate the rock-breaking process of hobs. In addition, an analysis was performed on the internal and kinetic energy involved in the rock-cutting and breaking processes under TBM hobs. The results show that the vertical force plays a major role in the rock-breaking process of the hob, and the values of the lateral force and the rolling force are small and do not affect it. The results obtained from this simulation can be used as boundary conditions for bearing analysis. Numerical and theoretical results were compared to verify the reasonability of the constructed constitutive model. [ABSTRACT FROM AUTHOR]

This study introduces a novel large three-dimensional physical model experimental system (PMES) for studying the geomechanical problems related to deep underground engineering. The apparatus is mainly composed of a counterforce frame, a hydraulic loading subsystem, a sample installation and transportation subsystem, an excavation subsystem, an integrated monitoring subsystem, and auxiliary facilities. During the design and development of the PMES apparatus, key technological issues were addressed. A high-stiffness frame structure with opening and closing function was developed. Uniform, gradient, and designed non-uniform stresses can be applied with high accuracy. An independent long-term load-holding unit and a surface dynamic disturbance unit were designed. The basic and innovative functions of the apparatus were verified through calibration experiments. A large physical model experiment was conducted to simulate the excavation of a deep-buried drainage tunnel in China's Jinping-II hydropower station. The experiment obtained the failure processes of the surrounding rock masses induced by high in-situ stress, specific engineering geological structures and excavation disturbance. The internal fracturing and strain evolution within the sample were successfully captured by the integrated monitoring subsystem. The results also validated the reliability of this novel apparatus. The development of this novel apparatus provides a new tool for the study of geomechanical problems in deep underground engineering. Highlights: A novel large three-dimensional physical model experimental system for studying the geomechanical problems related to deep underground engineering was established. The basic and innovative functions of the apparatus were verified through calibration experiments. A large physical model experiment was conducted to simulate the excavation of a deep tunnel in China's Jinping-II hydropower station. [ABSTRACT FROM AUTHOR]

Risk events can be frequently encountered in karst geological environments during excavation construction; thus, a suitable risk-control scheme is essential to reduce the negative impact of accidents. A decision-making approach based on the fuzzy VIKOR method is proposed to identify the optimal risk-control scheme, where a triangular fuzzy set is adopted to express the experts' judgements. A decision hierarchy is constructed based on four criteria and 12 sub-criteria, which are determined based on engineering experience and the construction environment. The developed approach was utilized to determine the optimal risk-control scheme to address risk events for excavation construction in karst regions. A countermeasure scheme, that is, pressure grouting with a two-phase liquid system, was implemented. The basic principles and steps of the implementation of the proposed scheme are presented. The applicability of the identified scheme was verified by the core recovery and modified number of blows using a standard penetration test. A flowchart of optimal scheme identification for geotechnical engineering practice is provided. [ABSTRACT FROM AUTHOR]

With the growing demand for transportation, there has been a significant increase in road-related projects, leading to potential risks in the safety of existing structures. This paper presents a study on the influence of new tunnel construction on the stability of an adjacent existing tunnel and provides valuable insights for the safety technology evaluation of similar tunnel crossing projects. In order to evaluate the influence of tunnel excavation on adjacent tunnels, the excavation process of a new tunnel near the original tunnel is simulated using the finite element software Midas GTS. This analysis includes the evaluation of static and dynamic responses. The results indicate that the horizontal and vertical displacements caused by the excavation of the railway tunnel are minimal. Furthermore, during the blasting excavation of the railway tunnel, the vibration velocity experienced by the highway tunnel remains below the safe allowable limit. These findings demonstrate that in this project, the influence of blasting excavation for the railway tunnel on the highway tunnel is both safe and manageable. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the design and construction of vacuum preloading incorporated with electroosmosis (VPE) engineering application for the treatment of soft soil on complex terrain for sluice foundation excavation in order to reduce the amount of cement used in construction. Monitoring was conducted during the VPE treatment and laboratory geotechnical tests were carried out once the treatment came to an end. Results show that the electrification mode has a significant influence on electric energy consumption. Stepped-up voltage helped in saving electric energy while electrode conversion consumed a lot of electric energy. The dispersion of soil parameters became larger after VPE treatment. The stability of physical parameters is better than the mechanical parameters, and the latter is better than the deformation parameters. Soil water content has a linear relationship with density and compression coefficient. The given linear fitting equations can help in simplifying the calculation and acquisition of these indexes. Although the mean values of the soil index parameters slightly improved, their coefficient of variation (COV) significantly increased. These locations with improved index parameters scattering in the construction site ensured that the subsequent construction tasks such as pit slope and excavation were successfully realized in this area. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fractured zone poses a significant risk to construction safety and structure durability in tunnel engineering. However, the effect of excavation methods has not been thoroughly investigated in previous studies. This paper presents a series of 1:30 scale 3D model tests on fault tunnels under the coupling effect of different fault dip angles and construction steps. We measured and analyzed the rock mass deformation and lining structure stress to explore the influence of tunnel excavation by the CD method. The model test results were verified by numerical simulation using the prototype tunnel parameters. Our results show that steeper fault dips correspond to greater radial pressure of the surrounding rock, and pressure in both haunt positions changes more significantly than that in the vault position, while pressure in the side-wall position changes only slightly. Additionally, considerable deformation can be observed in the vault and both haunt positions, with a rock mass relaxation range of less than 1.0 D. For the lining structure stress of each point in the second excavation cycle, larger lining stress is measured in the case of a fault dip of 75° than that in cases when the fault dip equals 45° and 60°, respectively. The biggest stress is observed in the side-wall position after the mid-partition is mantled to form a closed-loop lining structure. Overall, our findings provide valuable insights into the construction response of tunnels through faults and highlight the importance of considering excavation methods in tunnel engineering. [ABSTRACT FROM AUTHOR]

The current paper presents briefly and in general terms the horizontal geodesic survey done by angle measurement, as well as the engineering documentation of the results of the stage from the archaeological excavations of the site "Early (wooden) fortification" in the Inner city of Pliska in 2019. [ABSTRACT FROM AUTHOR]

With the rapid expansion of underground engineering, accurate settlement estimation during foundation excavation using monitoring data has gained prominence. Previous studies have typically overlooked data patterns, relying solely on time-series models, which yielded limited accuracy and short-term predictability. To address these issues, this paper performs a thorough pattern analysis covering both the temporal and spatial properties, and proposes a spatiotemporal modeling method grounded in explainable artificial intelligence technique. A real-world engineering case study is conducted to validate the effectiveness of the proposed method. Counterintuitively, the results reveal a weak temporal effect within the settlement data, with only the last step playing a dominant role, whereas the spatial correlation among measuring points is notably more significant. Compared to conventional models, the proposed method consistently outperforms, achieving significantly higher R2 scores and excelling in long-term estimation with reductions of at least 78% in RMSE, 80% in MAE, and 72% in MAPE. • Spatiotemporal pattern analysis and XAI modeling for estimation are performed. • Pattern analysis results shows weak temporal correlations of settlement. • Spatial correlations in measuring points persist across construction stages. • The method yields notably smaller RMSE, MAE, and MAPE than conventional models. • SHAP analysis results highly align with the patterns uncovered by data analysis. [ABSTRACT FROM AUTHOR]

• Operating shield tunnels affected by both the nearby and overlying excavation simultaneously in sensitive soft soils were investigated and presented. • The mechanism of improving the safety and serviceability of existing tunnels through tunnel reinforcement was revealed. • The impact of tunnel reinforcement on the adjacent existing tunnel during the construction stage was discussed. • Empirical methods estimating the impact range of side excavation, overlying excavation, and reinforcement construction were proposed. Adjacent engineering activities affect existing tunnels in service, causing safety concerns. Many studies have focused on single excavations overlying or parallel to adjacent existing tunnels. However, few have considered the responses of tunnels to multiple excavations with different orientations. In this study, the existing shield tunnels of Hangzhou Metro Lines 1, which were affected by both the nearby and overlying excavation simultaneously, in sensitive soft soils were investigated and presented. Field monitoring showed considerable displacement in the tunnels at different excavation stages. The interaction mechanism between the nearby and overlying excavation, the surrounding soil, and the existing tunnels was investigated by assessing the evolutionary pattern of the tunnel deformation. In addition, the mechanism of improving the safety and serviceability of tunnels through tunnel reinforcement, which has been ignored in past research, and the impact of tunnel reinforcement on the tunnel during the construction phase were evaluated. Empirical methods were proposed to estimate the impact range of nearby and overlying excavation and tunnel reinforcement construction. The results provide guidance for protecting metro tunnels during adjacent excavations in soft soils. [ABSTRACT FROM AUTHOR]

X. Li, D. Zhang, and Y. Hou [[21]] monitored ground deformation during the excavation process of shield tunnels in water-rich strata and verified the results using the numerical software FLAC 3D. Thus, secondary grouting of the existing tunnel should be carried out promptly before the tunnel underpass excavation. The first paper, authored by X. Li, Y. Yang, X. Li, and H. Liu [[14]], introduced three shield tunnel construction cases to acquire the main driving parameters for the evaluation of cutting head clogging. The second paper, prepared by J. Du, Q. Fang, J. Wang, and G. Wang [[2]], divided the process of a high-speed train passing through a railway tunnel into three stages, according to the spatial relationship between the train and the tunnel. [Extracted from the article]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The large deformation of soft rock is one of the most prominent problems in the deep tunnel during excavation, which brings serious potential safety hazards and economic losses. Understanding the deformation mechanism of soft rock is the key to resolving the large deformation issue. In this study, a series of physical and chemical experiments and mechanical experiments were conducted to examine the engineering properties of soft rock. In addition, field monitoring tests are implemented to observe the performance of soft rock during tunnel excavation. Through analyzing the deformation mechanism and law of soft rock, the relationship between the engineering properties of soft rock and performance under excavation of deep tunnel was established. The results showed that free swell rate of the rock samples is 10 ~ 25%, and the average swell force is 11 kPa, which indicated that the soft rock has a weak swell force. The mechanical properties of soft rocks such as the peak strength and elastic modulus under different confining pressures are also obtained. The results of field monitoring showed soft rock has a rapid short-term deformation and a slow long-term deformation property, and its short-term deformation even reaches 10 ~ 20 cm. In addition, the phenomenon of cross section shrinkage is prominent when tunnel passes the section of soft rock. The damage modes of soft rock tunnels can be classified as shotcrete layer fracture, steel arch distortion, collapse at the face. Moreover, some measures and suggestions are proposed to deal with the large deformation problem. [ABSTRACT FROM AUTHOR]

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Proposed a point cloud-based method for tunnel face discontinuity recognition. • Calculated optimal tunnel face plane to eliminate excavation profile interference. • Optimized fuzzy C-means(IFCM) algorithm for faster discontinuity identification. • Validated the method with a real tunnel face in northwest China. Current methods for identifying discontinuities in rock mass point clouds do not fully consider the unique characteristics of tunnel face rock masses. Excavation profiles reduce the accuracy of discontinuity characterization, and the short exposure time of tunnel face rock masses necessitates more efficient identification methods to guide excavation and support strategies. To address these issues, this paper proposes a new method for quickly characterizing discontinuities in tunnel face rock mass point clouds. This method automatically calculates the optimal tunnel face plane and uses distance thresholds to segment the tunnel face rock mass area from the excavation profile area, eliminating the influence of excavation profiles. Additionally, an optimized fuzzy C-means (OFCM) algorithm is designed to improve the accuracy and efficiency of discontinuity identification. The superiority of this method is demonstrated through three examples: polyhedral point clouds, a slope rock mass, and a tunnel face rock mass. In the slope point cloud test, the proposed method resulted in a dip difference of 2° and a dip direction difference of 0.6° compared with the DSE method, with an identification time of 52 s, compared with 7 min and 15 s for the DSE method. In a real tunnel face application in northwestern China, the proposed method showed an average difference from manual field measurements of 4.8° in the dip direction and 5° in the dip direction, with an identification time of 19 s, compared with 2 min and 52 s for the DSE method. Finally, this paper discusses the impact of distance threshold selection on the segmentation results and further verifies the method's generality through applications on four other tunnel faces. These results indicate that the proposed method is highly accurate and efficient in identifying discontinuities in tunnel face rock masses and can be effectively applied in practical engineering. [ABSTRACT FROM AUTHOR]

In order to improve the blasting effect of roadway excavation in a project the key parameters in the existing blasting scheme were optimized by theoretical calculation and LS DYNA numerical simulation method. Three groups of cutting and smooth blasting models were constructed respectively, and the factor D representing the damage was extracted. Based on this, the blasting effect was analyzed. The test results show that the double holes can provide good conditions for producing coherent cavities between cutting holes. Compared with the cutting blasting effect when the cutting hole spacing is 20 cm, 30 cm and 40 cm, it is found that the maximum cavity can be formed and penetrated when the spacing is 30 cm. Compared with the blasting effect of 30 cm, 40 cm and 50 cm light blasting hole spacing, with the increase of hole spacing, the damage zone between the two holes changed from through to not through, and the blasting effect can be best when the light blasting hole spacing is 40 cm. The above conclusions are applied to practical engineering, and it is found that the blasting effect is significantly improved. It is reasonable to apply the change law of rock damage to the improvement of blast hole spacing in tunnel excavation. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to reduce or avoid the disaster of rockburst during the construction of the long and deep tunnel TBM, the small pilot tunnel excavation technology to release the stress of the surrounding rock in the tunnel in advance was adopted, and the stress release effect through the microseismic monitoring equipment was monitored. The results showed that the excavation of the small pilot tunnel could effectively release the stress in the tunnel and reduce the intensity and frequency of rock bursts. On this basis, the effects of different single-shot doses and the cross-sectional dimensions of small pilot holes on stress release were studied. The results showed that the single-shot dose was basically proportional to the microseismic monitoring data, that was, within a certain range, the greater the single-shot dose was, the better the stress relief effect was; the larger the cross-section size was more conducive to stress relief. In actual engineering, the stress should be released as much as possible based on the actual situation and under the premise of ensuring safety. [ABSTRACT FROM AUTHOR]

To explicate the size of model boundary required for the analysis of ground settlement caused by circular tunnel excavation, the influences of the sizes of bottom boundary and horizontal boundary of the model on the ground settlement caused by a circular tunnel excavation were studied by the theoretical analysis and the numerical simulation. The Bobet, Park and Verruijt methods were adopted in the process of the theoretical analysis. The elastic and elastoplastic constitutive models were adopted in the process of the numerical simulation. The results of research showed that the mapping point of the circular tunnel vault on the ground surface gradually changed from settlement to uplift as the size of the model bottom boundary increased. When the model bottom was a half-space infinite body, the mapping point of the circular tunnel vault on the ground surface bulged infinitely. This phenomenon was obviously contrary to engineering reality. When there was an underlying hard layer at the model bottom boundary, if the elastic modulus of the underlying hard layer was 5 times that of the overlying soil, the underlying hard layer could be used as the bottom boundary condition of the model. The size of the model horizontal boundary was closely related to the size of the model bottom boundary and the tunnel radius. The size of the model horizontal boundary increased approximately linearly with the increased of the size of the model bottom boundary and the tunnel radius. [ABSTRACT FROM AUTHOR]

Civil engineering is a primary domain for new augmented reality technologies. In this work, the area of subsurface utility engineering is revisited, and new methods tackling well-known, yet unsolved problems are presented. We describe our solution to the outdoor localization problem, which is deemed one of the most critical issues in outdoor augmented reality, proposing a novel, lightweight hardware platform to generate highly accurate position and orientation estimates in a global context. Furthermore, we present new approaches to drastically improve realism of outdoor data visualizations. First, a novel method to replace physical spray markings by indistinguishable virtual counterparts is described. Second, the visualization of 3D reconstructions of real excavations is presented, fusing seamlessly with the view onto the real environment. We demonstrate the power of these new methods on a set of different outdoor scenarios. [ABSTRACT FROM AUTHOR]

It is very important to accurately determine the depth of excavation damaged zone for underground engineering excavation and surrounding rock stability evaluation, and it can be measured by acoustic test, but there is no quantitative method for analysis of the results, and it relies heavily on the experience of engineers, which leads to the low reliability of the results and also limits the application of the acoustic method. According to substantial field test data and the feedback of surrounding rock support parameters, the boundary method is proposed to determine the depth of excavation damaged zone in surrounding rock based on the relation between the ultrasonic velocity of measured point and the background wave velocity of rock mass. When the method is applied to the columnar jointed rock mass of Baihetan and the deep-buried hard rock of Jinping, the excavation damaged zone was well judged. The results in the Baihetan project show that the proposed method of determining excavation damage zone by the acoustic test can well demonstrate the anisotropy characteristics of the columnar jointed rock mass, and the damage evolution characteristics of jointed rock mass at the same position can also be obtained accurately. Moreover, the method also can accurately reveal the damage evolution process of the deep-buried hard rock under the condition of high ground stress, which proved the applicability of this method in jointed or nonjointed rock masses. [ABSTRACT FROM AUTHOR]

The suggested paper tries go present in brief and in general the types of archeological drawings when graphic engineering documenting of excavations at objects with cultural and historical heritage. [ABSTRACT FROM AUTHOR]

In the model test of underground engineering, how to carry out the automatic excavation of different types of tunnel and small caverns is still a technical challenge at present. In this paper, we designed and developed the micro automatic excavation device, including the cutting type automatic excavation device and the crushing type automatic excavation device for model test of underground engineering by using servo electric control technology. The device has high excavation accuracy. With the aid of this device, the excavation of cavern with any shape can be conducted. This device can carry out not only full section automatic excavation, but also bench method automatic excavation. The device has been successfully applied in the three-dimensional geomechanical model test of the excavation for the cavern groups in an underground laboratory. After the excavation of the model cavern, the wall of the cavern is smooth, and the intersection position and angle between the caverns are accurate. Compared with the design size, the excavation error of all caverns is within ± 5 ‰, which meets the design requirements. It provides technical support for accurate excavation test of model test meanwhile provides a strong technical guarantee for the fine simulation of the deformation characteristics and failure laws of deep underground caverns. [ABSTRACT FROM AUTHOR]

Many engineering projects and interventions have negative effects on the environment. Rock excavation in civil engineering, either in mining or in construction, often is unthinkable without the use of explosive. However, blasting can have extensive adverse environmental impacts, like vibrations, noise, dust and chemical contamination. Therefore, it is better to avoid blasting activities near urban areas, protected animal habitats, sensitive historic buildings, water protection zones, pipelines, etc. While mechanical excavation is often longer lasting and more expensive, in some cases it may adequately replace blasting, where the applicability of mechanical excavation methods greatly dependent on the rock mass characteristics which should excavate. This paper provides practical examples of using existing methods for the assessment of the applicability of excavation technologies. In order to minimize the project impact on the environment, mechanical excavation was applied in some cases. In one case, the blasting could not be avoided, but controlled careful blasting techniques were applied. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)