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Surrounding rock pressure in the tunnel portal section through moraine under freeze-thaw action

Journal of Mountain Science 2024年第7期21卷 2480-2493页

作者： CHEN Zhimin LIU Baoli LIU Yaohui XU Jiangtao School of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730070China CSCEC AECOM Consultants Co. ltdLanzhou 730000China National and Local Joint Engineering Laboratory of Road and Bridge Engineering disaster prevention Technology Lanzhou Jiaotong UniversityLanzhou 730070China

Moraines,characterized by the accumulation of rock and soil debris transported by glacial activity,present unique challenges for tunnel construction,particularly in portal sections,due to prevailing geographical and climatic conditions that facilitate freeze-thaw *** these challenges,there is a dearth of studies investigating the influence of freeze-thaw action and water content on the mechanical properties of moraines,and no research on calculating surrounding rock pressure in moraine tunnels subjected to freeze-thaw *** this study,direct shear tests under freeze-thaw cycles were conducted to examine the effects of freeze-thaw cycles and water content on the mechanical properties of frozen moraine.A comprehensive parameter K,integrating the number of freeze-thaws and water content,was introduced to model cohesion *** on Terzaghi Theory,we propose an improved algorithm for calculating surrounding rock pressure at the portal section of moraine *** a tunnel as a case study,surrounding rock pressure was calculated under various conditions to validate the Improved Algorithm's *** results show that:(1)Strength loss exhibits a linear trend with the number of freeze-thaw cycles at water content levels of 4%and 8%,while at 12%water content,previous freeze-thaw cycles induce more significant damage to the soil.(2)Moraine saturation peaks between 8%and 12%water *** repeated freeze-thaw cycles,moraine shear strength initially increases before decreasing with varying water content.(3)The internal friction angle of moraine experiences slight reductions with prolonged freeze-thaw cycles,but both freeze-thaw cycles and water content significantly influence cohesion.(4)Vertical surrounding rock pressure increases after the initial freeze-thaw cycle,particularly with higher water content,although freeze-thaw cycles have minimal effect on it.(5)Freeze-thaw cycles lead to a substantial increase in lateral surrounding rock pre

关键词： Moraines Freeze-thaw cycles Direct shear test Surrounding rock pressure

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Modified Sadowski formula-based model for the slope shape amplification effect under multistage slope blasting vibration

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International Journal of Mining Science and Technology 2024年第5期34卷 631-641页

作者： Xiaogang Wu Mingyang Wang Hao Lu Yongjun Zhang Wen Nie State Key Laboratory of disaster prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China State Key Laboratory of Metal Mine Safety and Health Ma’anshan 243000China School of Civil Engineering Qingdao University of TechnologyQingdao 266520China

Blasting operations,which are crucial to open-pit mine production due to their simplicity and efficiency,require precise control through accurate vibration velocity *** conventional Sadowski formula mainly focuses on blast center distance but neglects the amplification effect of blasting vibration waves by terraced terrain,from which the calculated blasting vibration velocities are smaller than the actual values,affecting the safety of the *** address this issue,our model introduces the influences of slope and time into Sadowski formula to measure safety through blast vibration *** the northern section of the open-pit quartz mine in Jinchang City,Gansu Province,China,the data of a continuous blasting slope project are referred *** findings reveal a noticeable vibration amplification effect during blasting when a multi-stage slope platform undergoes a sudden cross-sectional change near the upper overhanging *** amplification vibration coefficient increases with height,while vibration waves within rocks decrease from bottom to ***,platforms without distinct crosssectional changes exhibit no pronounced amplification during *** addition,the vibration intensity decreases with distance as the rock height difference change *** results obtained by the proposed blast vibration displacement equation incorporating slope shape influence closely agree with real-world *** to Pearson correlation coefficient(PPMCC)analysis,the average accuracy rate of our model is 88.84%,which exceeds the conventional Sadowski formula(46.92%).

关键词： Multistage slope Slope shape influence factor Continuous blasting Sadowski formula Amplification effect

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Simulation of Fracture Process of Lightweight Aggregate Concrete Based on Digital Image Processing Technology

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Computers, Materials & Continua 2024年第6期79卷 4169-4195页

作者： Safwan Al-sayed Xi Wang Yijiang Peng Key Laboratory of Urban Security and disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China

The mechanical properties and failure mechanism of lightweight aggregate concrete(LWAC)is a hot topic in the engineering field,and the relationship between its microstructure and macroscopic mechanical properties is also a frontier research topic in the academic *** this study,the image processing technology is used to establish a micro-structure model of lightweight aggregate *** the information extraction and processing of the section image of actual light aggregate concrete specimens,the mesostructural model of light aggregate concrete with real aggregate characteristics is *** numerical simulation of uniaxial tensile test,uniaxial compression test and three-point bending test of lightweight aggregate concrete are carried out using a new finite element method-the base force element method ***,the image processing technology is used to produce beam specimens,uniaxial compression specimens and uniaxial tensile specimens of light aggregate concrete,which can better simulate the aggregate shape and random distribution of real light aggregate ***,the three-point bending test is numerically ***,the uniaxial compression specimen generated by image processing technology is numerically ***,the uniaxial tensile specimen generated by image processing technology is numerically *** mechanical behavior and damage mode of the specimen during loading were *** results of numerical simulation are compared and analyzed with those of relevant *** feasibility and correctness of the micromodel established in this study for analyzing the micromechanics of lightweight aggregate concrete materials are *** processing technology has a broad application prospect in the field of concrete mesoscopic damage analysis.

关键词： Digital image processing lightweight aggregate concrete mesoscopic model numerical simulation fracture analysis bending beams

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Development of component stiffness equations for thread-fixed one-side bolt connections to an enclosed rectangular hollow section column under tension

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 568-586页

作者： Fu-Wei WU Yuan-Qi LI Department of Structural Engineering Tongji UniversityShanghai 200092China State Key Laboratory of disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

The derivation and validation of analytical equations for predicting the tensile initial stiffness of threadfixed one-side bolts(TOBs),connected to enclosed rectangular hollow section(RHS)columns,is presented in this *** unknown stiffness components are considered:the TOBs connection and the enclosed RHS ***,the trapezoidal thread of TOB,as an equivalent cantilevered beam subjected to uniformly distributed loads,is analyzed to determine the associated *** on the findings,the thread-shank serial-parallel stiffness model of TOB connection is *** analysis of the tensile stiffness of the enclosed RHS face due to two bolt forces,the four sidewalls are treated as rotation constraints,thus reducing the problem to a two-dimensional plate *** to the load superposition method,the deflection of the face plate is resolved into three components under various boundary and load *** to the plate deflection theory of Timoshenko,the analytical solutions for the three deflections are derived in terms of the variables of bolt spacing,RHS thickness,height to width ratio,***,the validity of the above stiffness equations is verified by a series of finite element(FE)models of T-stub *** proposed component stiffness equations are an effective supplement to the component-based method.

关键词： initial stiffness component based method thread-fixed one-side bolt rectangular hollow sections analytical equation

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Proper interpretation of sectional analysis results

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Earthquake Research Advances 2024年第2期4卷 65-71页

作者： Juyuan Zheng Yuli Huang Zhe Qu Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin150080China Key Laboratory of Earthquake disaster Mitigation Ministry of Emergency ManagementHarbin150080China Arup 560 Mission StreetSuite 700San FranciscoCA94105United States

Displacement control algorithms commonly used to evaluate axial force-bending moment(PM)diagrams may lead to incorrect interpretations of the strength envelopes for asymmetric *** paper aims to offer valuable insights by comparing existing displacement control algorithms with a newly proposed force control *** main focus is on the PM diagrams of three example sections that exhibit varying degrees of *** comparative study indicates that conventional displacement control algorithms inevitably introduce non-zero out-of-plane bending *** reported PM diagram in such cases erroneously neglects the out-of-plane moment and fails to represent the strength envelope *** oversight results in significant and unconservative errors when verifying the strength of asymmetric sections.

关键词： Fiber section model Axial force-moment interaction diagram Limit state Failure surface

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Seismogenic Structure of the 1605 Qiongshan M7½ Earthquake and Its Holocene Activity History in Northern Hainan Island, China: Evidence from Cross-section Drilling and Shallow Seismic Profile

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Journal of Earth Science 2024年第3期35卷 905-917页

作者： Chaoqun Wang Liyun Jia Daogong Hu Shibiao Bai Zhengwang Hu Dongxia Sun Xiaoxiao Yang Lei Zhang Xiumin Ma Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China Key Laboratory of Active Tectonics and Geological Safety Ministry of Natural ResourcesBeijing 100081China Key Laboratory of Geohazard prevention of Hilly Mountains Ministry of Land and Resources(Fujian Key Laboratory of Geohazard Prevention)Fuzhou 350002China Observation and Research Station of Crustal Stress and Strain in Beijing Ministry of Natural ResourcesBeijing 100081China College of Marine Science and Engineering Nanjing Normal UniversityNanjing 210023China Hubei Subsurface Multi-Scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China

The 1605 M7½ Earthquake is the only earthquake in the history of China that has caused large-scale land subsidence into the sea,with the total area of land subsidence exceeding 100 *** disaster has led to the sinking of 72 *** is still no clear understanding of the source seismogenic fault of this *** this work,we conducted a detailed study of the middle segment of the Maniao-Puqian fault(MPF),which is the epicenter area,through geomorphological survey,data collection,shallow seismic exploration,cross-section drilling,and chronological *** results showed that the middle segment of the MPF zone is composed of three nearly parallel normal faults with a dextral strike-slip:“Macun-Luodou fault(F2-1),Haixiu-Dongyuan fault(F2-2),and ChangliuZhuxihe fault(F2-3)”.And F2-2 is composed of two secondary faults,namely F2-2′and F2-2″,with a flower-shaped structure buried under the *** is distributed nearly east-west,dipping to the north and has experienced at least five stages of activities since the *** vertical activity rates of F2-2′and F2-2″are~2.32 and~2.5 mm/a,since the Holocene,*** were eight cycles of transgression and regression since the *** fault activity resulted in the thickening of the Holocene strata with a slight dip to the south,on the hanging wall,showing V-shaped *** MPF is likely the source seismogenic fault of the M7½ earthquake that hit Qiongshan in 1605.

关键词： seismogenic structure earthquakes Maniao-Puqian fault fault activity history geomorphology.

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Development of pharmacological immunoregulatory anticancer therapeutics:current mechanistic studies and clinical opportunities

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Signal Transduction and Targeted Therapy 2024年第6期9卷 2477-2526页

作者： Nanhao Yin Xintong Li Xuanwei Zhang Shaolong Xue Yu Cao Gabriele Niedermann You Lu Jianxin Xue Division of Thoracic Tumor Multimodality Treatment Cancer Center&State Key Laboratory of Biotherapyand The National Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityNo.37Guoxue LaneChengdu 610041 SichuanPR China Department of Gynecology and Obstetrics West China Second University HospitalSichuan UniversityNo.20Section 3South Renmin RoadChengdu 610041 SichuanPR China Department of Emergency Medicine Laboratory of Emergency MedicineWest China HospitalSichuan UniversityNo.37Guoxue LaneChengdu 610041 SichuanPR China Institute of disaster Medicine&Institute of Emergency Medicine Sichuan UniversityNo.17Gaopeng AvenueChengdu 610041 SichuanPR China Department of Radiation Oncology Medical Center—University of FreiburgFaculty of MedicineUniversity of FreiburgGerman Cancer Consortium(DKTK)Partner Site DKTK-FreiburgRobert-Koch-Strasse 379106 FreiburgGermany Laboratory of Clinical Cell Therapy West China HospitalSichuan UniversityNo.2222Xinchuan RoadChengdu 610041 SichuanPR China

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment,but challenges related to resistance and toxicity still *** to the advancement of immuno-oncology,an increasing number of novel immunoregulatory targets and mechanisms are being revealed,with relevant therapies promising to improve clinical immunotherapy in the foreseeable ***,comprehending the larger picture is *** this review,we analyze and summarize the current landscape of preclinical and translational mechanistic research,drug development,and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint *** with further clarification of cancer immunobiology and advances in antibody engineering,agents targeting additional inhibitory immune checkpoints,including LAG-3,TIM-3,TIGIT,CD47,and B7 family members are becoming an important part of cancer immunotherapy research and discovery,as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T *** by bispecific T cell engagers,newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical ***-generation agents also include immune epigenetic drugs and cytokine-based *** therapies,cancer vaccines,and oncolytic viruses are not covered in this *** comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

关键词： clinical immuno landscape

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Estimation of debris flow discharge coefficient considering sediment concentration

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International Journal of Sediment Research 2019年第1期34卷 1-7页

作者： Namgyun Kim Hajime Nakagawa Kenji Kawaike Hao Zhang Department of Civil and Earth Resource Engineering Kyoto University 2. Disaster Prevention Research CenterKyoto University disaster prevention section Science Research CenterKochi University

A sabo dam has a purpose to block the path of debris flow. However, when overflow occurs, a sabo dam works as a weir, a vertical obstruction, where the fluid must flow over. Many empirical formulas and discharge coefficients for weirs relating flow depth to discharge have been proposed to calculate overflow discharges. However, only a few studies about overflow discharge coefficients are available in the case of debris flow. In this paper, experiments and numerical simulations were done to estimate debris flow discharge coefficients by considering the sediment concentration. In the numerical simulation, a complete overflow equation and a free overfall equation were implemented to calculate debris overflow discharges at a sabo dam. To determine the discharge coefficients for each equation, single factor regression analysis was used. Laboratory experiments were done to calibrate and to compare with the simulation. Study results showed that the discharge coefficients increase as the sediment concentration increases. This finding suggests debris flow discharge coefficients are derived to calculate the debris overflow discharges at a sabo dam.

关键词： Numerical simulation Debris flow Sabo dam Discharge coefficient

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Numerical optimization on differential adjusting measures for asymmetrical degenerated warm permafrost railway embankment

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Advances in Climate Change Research 2023年第3期14卷 479-491页

作者： Yan-Dong HOU Wen-Yuan LEI Shu-Hao LIANG Ming-Li ZHANG Feng-Xi ZHOU School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of disaster prevention and Mitigation in Civil Engineering of Gansu Province Lanzhou University of TechnologyLanzhou 730050China

Affected by climate warming and shady–sunny slope effect,the permafrost foundation under the railway is undergoing a significant asymmetric degradation process;research on the corresponding regulating or strengthening measures is urgently *** on a well developed of numerical model,we analyzed the‘thermal repair’effect of three redesigned differential thermal reinforcement on the partially degraded permafrost embankment with *** results show that,when used as a strengthening measure,the method of laying crushed rock revetment(CRR)with different thicknesses on the sunny and shady slopes cannot completely eliminate the residual warm permafrost regions formed in the previous thermal *** the TCRR scheme is adopted for reinforcement,although horizontal region from the evaporation section of thermosyphones(TPCTs)to the right side of the embankment is remarkably cooled,permafrost under the sunny slope is still *** the long run,both ETCRR and TCECRR reinforcement schemes can produce a large range of‘cold core’right below the whole ***,from the perspective of the simultaneous functioning range and cold storage capacity,the TCECRR scheme is signally more *** thermal insulation materials in the above composite strengthening measures can not only resist the heat input in the warm season,but also improve their working efficiency by maintaining the temperature difference between the evaporation section of the heat pipe and the external environment in cold *** addition of crushed rock revetment in TCECRR has played its thermal semiconductor effect and further improved the comprehensive thermal repair efficiency of the composite measures.

关键词： Asymmetric degradation Crushed rock revetment Thermal insulation materials TPCT Reinforcement

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Active faults and seismogenic models for the Urumqi city,Xinjiang Autonomous Region, China

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Earthquake Science 2016年第3期29卷 173-184页

作者： Yingzhen Li Yang Yu Jun Shen Bo Shao Gao Qi Mei Deng Institute of disaster prevention

We have studied the characteristics of the active faults and seismicity in the vicinity of Urumqi city, the capital of Xinjiang Autonomous Region, China, and have proposed a seismogenic model for the assessment of earthquake hazard in this area. Our work is based on an integrated analysis of data from investigations of active faults at the surface, deep seismic reflection soundings, seismic profiles from petroleum exploration, observations of temporal seismic stations, and the precise location of small earthquakes. We have made a comparative study of typical seismogenic structures in the frontal area of the North Tianshan Mountains, where Urumqi city is situated, and have revealed the primary features of the thrust-fold- nappe structure there. We suggest that Urumqi city is comprised two zones of seismotectonics which are inter- preted as thrust-nappe structures. The first is the thrust nappe of the North Tianshan Mountains in the west, con- sisting of the lower （root） thrust fault, middle detachment, and upper fold-uplift at the front. Faults active in the Pleistocene are present in the lower and upper parts of this structure, and the detachment in the middle spreads toward the north. In the future, M7 earthquakes may occur at the root thrust fault, while the seismic risk of frontal fold-uplift at the front will not exceed M6.5. The second structure is the western flank of the arc-like Bogda nappe in the east, which is also comprised a root thrust fault, middle detachment, and upper fold-uplift at the front, of which the nappe stretches toward the north; several active faults are also developed in it. The fault active in the Holocene is called the South Fukang fault. It is not in the urban area of Urumqi city. The other three faults are located in the urban area and were active in the late Pleistocene. In these cases, this section of the nappe structure near the city has an earthquake risk of M6.5-7, An earthquake Ms6.6, 60 km east to Urumqi city occurred along the

关键词： Urumqi Active fault Seismogenic structure Thrust Nappe

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