Numerical simulation research on response characteristics of surrounding rock for deep super-large section chamber under dynamic and static combined loading condition

The stability control of surrounding rock for large or super-large section chamber is a difficult technical problem in deep mining condition.Based on the in-site geological conditions of Longgu coal mine,this paper used the dynamic module of FLAC3D to study the response characteristics of deep super-large section chamber under dynamic and static combined loading condition.Results showed that under the static loading condition,the maximum vertical stress,deformation and failure range are large,where the stress concentration coefficient is 1.64.The maximum roof-to-floor and two-sides deformations are 54.6 mm and 53.1 mm,respectively.Then,under the dynamic and static combined loading condition:(1)The influence of dynamic load frequency on the two-sides is more obvious;(2)The dynamic load amplitude has the greatest influence on the stress concentration degree,and the plastic failure tends to develop to the deeper;(3)With the dynamic load source distance increase,the response of surrounding rock is gradually attenuated.On this basis,empirical equations for each dynamic load conditions were obtained by using regression analysis method,and all correlation coefficients are greater than 0.99.This research provided reference for the supporting design of deep super-large section chamber under same or similar conditions.

A super-large graphite deposit discovered in granite rocks at Huangyangshan, Xinjiang,China

1.Objective A graphite deposit has been discovered in Sujiquan, Xinjiang in 1980s,which provides detailed geological settings for the super-large graphite deposit discovered in Huangyangshan pluton with total reserves up to 7.264×10^9 t in 2017.Outcrops of igneous rocks in the study area include Middle Devonian plagioclase granite and Late Carboniferous alkali feldspar granite that is referred to the Huangyangshan pluton,which includes the Lower Carboniferous Heishantou Formation and Jiangbasi Formation,both of which consist of volcanic-sedimentary rocks (Fig.1).Sujiquan fault provided passage for the migration of volcanic intrusions.Graphite deposits are usually hosted by metamorphic rocks,but Huangyanshan deposits are hosted by granite rocks,which are rarely known.The Huangyangshan graphite deposit hosted by granite pluton at Huangyangshan area was discovered by Xinjiang Branch of China National Geological Exploration Center of Building Materials Industry since 2015.

New Zircon U-Pb Age of the Super-Large Lijiagou Spodumene Deposit in Songpan Garze Fold Belt, Eastern Tibet： Implications for Early Jurassic Rare-Metal Polymetallic Event

Objective The Songpan-Garze Fold Belt(SGFB),located in the eastern part of the Tibet Plateau and west of the Sichuan Basin,is an important pegmatite province in China.Some famous pegmatite type deposits occur in the SGFB,including the Xuebaoding,Jiajika,Keeryin rare metal deposits and Danba muscovite deposit(Li Jiankang et al.,2015).The newly discovered super-large Lijiagou

Bainiuchang super-large silver-polymetallic ore deposit related to granitic magmatism in Mengzi, Yunnan

Bainiuchang silver-polymetallic ore deposit is located in the southeast Yunnan tin-polymetallic metallogenic belt.The probable reserves and inferred resources of the deposit are of 6 470 t Ag and 1.10 Mt Pb and 1.72 Mt Zn and 86 kt Sn.Orebodies of the deposit occur in clastic-carbonate rocks of Tianpeng Formation and Longha Formation of the middle Cambrian System above the Bainiuchang concealed granite of the late Yanshan period.The concealed granite has the characteristics of tin-bearing granites.Abundance of the mineralization elements Sn,Cu,Zn,Pb,Ag and Sb is high in the granitic rocks.Sulphur isotope data of the metal sulphides indicate that most sulphur is derived from the magmas.The ores are similar in rare earth element(REE)patterns to the granitic rocks.The granitic magma activity results in ore-bearing structures.Rocks of the Middle Cambrian System above the concealed intrusion suffer from skarnization,hornfelsing,marbleization,siliconizing and carbonatization.The mineralization elements Sn,Cu,Zn,Pb,Ag and Sb successively appear from the top of the granite to surrounding rocks.These evidences indicate that the granitic magmatism is the principal mineralization factor.The opinion that the south Bainiuchang ore field and the north Awei ore block are tin and copper potential exploration areas was put forward and was verified by drilling tests.

Instability energy mechanism of super-large section crossing chambers in deep coal mines

The stress concentration and failure at chamber intersections in coal mine are intense,especially in deepburied,super-large section conditions.In this paper,the plastic radius of super-large section chamber under unequal pressure was corrected on the basis of the size effect.Then,stress and failure evolution of intersections under different crossing angles and equivalent angular bisectors were revealed.Furthermore,2 trajectory curves of failure and stress were analytically expressed,which divided the intersection into 5 influencing zones in the light of stress superposition degree.After determining instability trigger point and instability path,instability energy criterion of intersection can be obtained as K>1,which means that the external energy is greater than the sum of energy consumed by surrounding rock instability and supporting structure failure.Taking coal-gangue separation system of Longgu Coal Mine as example,it was found that there was instability risk under original parameters.For long-term stability,an optimization design method was proposed by considering safety factor,and optimal support scheme was obtained.Field monitoring showed intersections deformations were relatively small with the maximum of 125 mm,which verified the rationality of theoretical analysis.This study provides guidance for the stability control of the intersections under the same or similar conditions.

Wind-induced responses of super-large cooling towers

Traditional gust load factor(GLF)method,inertial wind load(IWL)method and tri-component method(LRC+IWL)cannot accurately analyze the wind-induced responses of super-large cooling towers,so the real combination formulas of fluctuating wind-induced responses and equivalent static wind loads(ESWLSs)were derived based on structural dynamics and random vibration theory.The consistent coupled method(CCM)was presented to compensate the coupled term between background and resonant response.Taking the super-large cooling tower(H=215 m)of nuclear power plant in Jiangxi Province,China,which is the highest and largest in China,as the example,based on modified equivalent beam-net design method,the aero-elastic model for simultaneous pressure and vibration measurement of super-large cooling tower is firstly carried out.Then,combining wind tunnel test and CCM,the effects of self-excited force on the surface pressures and wind-induced responses are discussed,and the wind-induced response characteristics of background component,resonant component,coupled term between background and resonant response,fluctuating responses,and wind vibration coefficients are discussed.It can be concluded that wind-induced response mechanism must be understood to direct the wind resistant design for super-large cooling towers.

Magmatic Evolution and Mineralization Process of the Super-Large Shihuiyao Rb–Nb–Ta Deposit,Southern Great Xing'an Range,China

Rare metal ore reserves are an important strategic resource, and their metallogenic mechanism and mineralization studies have also been received widespread international attention.

Two Super-Large Gold Deposits Have Been Discovered in Jiaodong Peninsula of China

During 2015, gold prospecting in Laizhou City of Shandong Peninsula in China has achieved a major breakthrough. Deposits containing 470 and 389 tons of gold metal were discovered in the northern sea area of Sanshandao and the Shaling area, respectively. As a result, the gold prospective resources in the entire Jiaodong Peninsula have now exceeded 4000 tons, fully indicative of the super-large prospecting potential of the Jiaojia-type deposits.

A Super-Large Rb-Nb Rare Metal Deposit has been Discovered in Huashi Village of Xinglong County, Hebei Province

Objective The Huashi Village in Xinglong County of Hebei Province is located in the Yanshan subsidence zone in the central eastern North China Plate, which is 137 km away from Beijing City （Fig. la）. This area has undergone large -scale magmatic intrusion affected by the tectonic compression of the Pacific Plate in the Mesozoic （known as the Yanshanian movement） to form many alkaline rocks such as the Wulingshan rock mass. Previous studies have conducted petrological research and reconnaissance survey of rare metal ores in this area （Tian Shuzhang and Guo Zongshan, 1981; Xu Baoling et al., 1996）. In 2016, the Qinhuangdao Mineral and Hydrology Engineering Geological Brigade of Hebei Bureau of Geology and Mineral Resources Exploration implemented the project of Reconnaissance of Rare Metal Ores Including Rubidium in Huashi Village of Xinglong County, Hebei Province, and discovered super-large rare metal deposits of rubidium and biobium in the Madi alkali feldspar granite bodies in the Huashi Village to achieve great breakthrough of rare metal ore prospecting.

The Major Ore Clusters of Super-Large Iron Deposits in the World, Present Situation of Iron Resources in China, and Prospect

The metamorphosed sedimentary type of iron deposits（BIF） is the most important type of iron deposits in the world, and super-large iron ore clusters of this type include the Quadrilatero Ferrifero district and Carajas in Brazil, Hamersley in Australia, Kursk in Russia, Central Province of India and Anshan-Benxi in China. Subordinated types of iron deposits are magmatic, volcanic-hosted and sedimentary ones. This paper briefly introduces the geological characteristics of major super-large iron ore clusters in the world. The proven reserves of iron ores in China are relatively abundant, but they are mainly low-grade ores. Moreover, a considerate part of iron ores are difficult to utilize for their difficult ore dressing, deep burial or other reasons. Iron ore deposits are relatively concentrated in 11 metallogenic provinces（belts）, such as the Anshan-Benxi, eastern Hebei, Xichang-Central Yunnan Province and middle-lower reaches of Yangtze River. The main minerogenetic epoches vary widely from the Archean to Quaternary, and are mainly the Late Archean to Middle Proterozoic, Variscan, and Yanshanian periods. The main 7 genetic types of iron deposits in China are metamorphosed sedimentary type（BIF）, magmatic type, volcanic-hosted type, skarn type, hydrothermal type, sedimentary type and weathered leaching type. The iron-rich ores occur predominantly in the skarn and marine volcanic-hosted iron deposits, locally in the metamorphosed sedimentary type（BIF） as hydrothermal reformation products. The theory of minerogenetic series of mineral deposits and minerogenic models has applied in investigation and prospecting of iron ore deposits. A combination of deep analyses of aeromagnetic anomalies and geomagnetic anomalies, with gravity anomalies are an effective method to seeking large and deep-buried iron deposits. China has a relatively great oresearching potential of iron ores, especially for metamorphosed sedimentary, skarn, and marine volcanic-hosted iron deposits. For the lower guarantee degree of iron and steel industry, China should give a trading and open the foreign mining markets.

Application of Tectono Geochemical Study in Deep Concealed Ore Body Exploration--As the Huize Super-Large Lead-Zinc Deposit an exemple

1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou

Source of the Ore-forming Adakitic Porphyry at the Beiya Super-large Au Deposit, Western Yangtze Craton: New Evidence from Zircon U-Pb Ages of the Amphibolite Xenoliths

Objective The Beiya super-large Au-rich porphyry deposit(304 t Au,2.4 g/t Au)is located within the western Yangtze craton,to the southeast of the Sanjiang Tethyan Orogen(Fig.1).The ore-forming porphyry is adakitic,characterized by high Sr/Y and La/Yb ratios coupled with low Y and Yb contents,and is generally thought to be derived from partial melting of thickened mafic lower crust.The lower crust underneath the western Yangtze craton is mainly composed of ancient crust with Archean ages,juvenile crust resulting from the Neoproterozoic subduction(740–1000 Ma),and late Permian juvenile crust related to the Emeishan mantle plume.Which lower crustal end-member has played a critical role in genesis of the Beiya ore-forming porphyry can be constrained by zircon U-Pb ages of amphibolite xenoliths hosted in the ore-forming porphyry,because these xenoliths represent direct samples of the source.In this study,we present new zircon U-Pb ages of these amphibolite xenoliths to have insight into the nature of the Beiya adakitic porphyry source.

Super-Large Pb-Zn Deposits Discovered in Danaopo,Huayuan County,Hunan Province

Geological Brigade 405 of Hunan Provincial Geology and Mineral Exploration and Development Bureau discovered the Danaopo and Yangjiazhai super-large Pb- Zn deposits through 5 years （2009-2014） of exploration in Huayuan County, Hunan Province. These deposits contain 208.4942 million tons of （332＋333） class Pb＋Zn ores and 4.8746 million tons of metal amounts, of which metal amounts of 333 class zinc are 4.1198 million tons and metal amounts of lead are 0.7548 million tons, associated with useful components of Cd, Ag and Se. In addition, the Limei, Qingshuitang and Yutang Pb-Zn deposits were proven betbre and this region has thus been ranked as a Pb-Zn ore resource base with a hundred-ton scale （Fig. 1）.

Super-Large Manganese Deposits Have Been Discovered at Pujue and Taoziping,Songtao County in Guizhou Province

In 2016,the Geological Brigade No.103 of Guizhou Geology and Mineral Exploration and Development Bureau discovered two super-large manganese deposits at Pujue and Taoziping,in Songtao County,Guizhou Province（Fig.1）.The Pujue manganese deposit has191.59 million tons of proven（332＋333）class ore reserves,including 35.54 million tons of 332 class and

Breeding of Super-large-grain Wheat Germplasms

[Objectives]This study was conducted to breed high-yielding wheat varieties. [Methods] A new breeding technology of "Artificial mutagenesis to increase genetic differences between parents and to enhance heterosis" was put forward. Longnan 71 a and Longnan 71 a mutants bred by this technology were crossed with other mutants and normal materials. [Results] In the Wudu experimental field of Longnan City, the traits of super-large grain appeared in the obverse and inverse cross with Longnan 71 a as parents. The trait of super-large grain was dominantly inherited. The traits of various combinations in the Fgeneration were segregated. In the Fgeneration, one super-large-grain low-stalk line and other lines with specific traits were selected. In the Fgeneration, two super-large-grain low-stalk large-ear lines were selected. These three super-large-grain low-stalk wheat lines had reduced plant height and good lodging resistance, and possessed two high-yielding characters among the three factors of yield, so they were expected to be further bred into high-yielding wheat varieties. One line with the largest grain length of 10.3 mm was selected in the Fgeneration. After two years of breeding, in 2022, the largest grain length was measured to be 10.6 mm, and the average 1 000-grain weight and the largest 1 000-grain weight were 75.8 and 100 g, respectively. [Conclusions] This study is about the major progress in artificial cultivation of super-large-grain wheat and has considerable practical value.

The Newly Discovered Super-Large Wulashan-Hademengou Gold Metallogenic Belt in Inner Mongolia,China Has Gold Reserves of Over 100 Tons

The Wulashan-Hademengou gold ore district in Baotou city, Inner Mongolia, is a further newly discovered super-large gold metallogenic belt in northern China. The accumulated proven gold metal amount is 84.46 t, with an average grade of 3.53 g/t and a gold metal amount of 63.16 t, with an average grade of 3.30 g/t. The potential reserves are over 100 t.

Data-driven real-time prediction for attitude and position of super-large diameter shield using a hybrid deep learning approach

The presented research introduces a novel hybrid deep learning approach for the dynamic prediction of the attitude and position of super-large diameter shields-a critical consideration for construction safety and tunnel lining quality.This study proposes a hybrid deep learning approach for predicting dynamic attitude and position prediction of super-large diameter shield.The approach consists of principal component analysis(PCA)and temporal convolutional network(TCN).The former is used for employing feature level fusion based on features of the shield data to reduce uncertainty,improve accuracy and the data effect,and 9 sets of required principal component characteristic data are obtained.The latter is adopted to process sequence data in predicting the dynamic attitude and position for the advantages and potential of convolution network.The approach’s effectiveness is exemplified using data from a tunnel construction project in China.The obtained results show remarkable accuracy in predicting the global attitude and position,with an average error ratio of less than 2 mm on four shield outputs in 97.30%of cases.Moreover,the approach displays strong performance in accurately predicting sudden fluctuations in shield attitude and position,with an average prediction accuracy of 89.68%.The proposed hybrid model demonstrates superiority over TCN,long short-term memory(LSTM),and recurrent neural network(RNN)in multiple indexes.Shapley additive exPlanations(SHAP)analysis is also performed to investigate the significance of different data features in the prediction process.This study provides a real-time warning for the shield driver to adjust the attitude and position of super-large diameter shields.

Deformation characteristics and instability mechanism of transportation hub under downward traversal conditions of the double-track super-large diameter shield tunnel

To investigate the deformation characteristics and instability mechanism of the transportation hub underdownward traversal conditions of the double-track super-large diameter shield tunnel, take the example of BeijingEast Sixth Ring Road into the ground reconstruction project. Using the field experimental monitoring method andnumerical simulation method, after verifying the accuracy of the model, this manuscript begins to unfold theanalysis. The results show that, without any deformation prevention and control measures, The basement raft ofthe underground structure of the transportation hub will produce a deformation difference of 18 mm, and thetensile stress is more than 1.43 MPa, the inhomogeneous deformation and structural cracking will lead tostructural instability and groundwater surges, which seriously affects the safe operation of the transportation hubstation. When control measures are taken, the deformation and stress of the base raft slab of the undergroundstructure of the transportation hub are within the prescribed limits, which can ensure the safe operation of thestation. The displacement of the base slab of the underground structure in the horizontal direction of the crosssection is all pointing to the east, and the overall trend is to shift from the first tunnel to the backward tunnel. Thehorizontal displacement of the base slab in the direction of the tunnel axis all points to the beginning of thecrossing, and the displacement of the slab in the vertical direction is distributed as "rising in the middle andsinking in the surroundings". For a two-lane super-large diameter shield tunnel penetrating an undergroundstructure, there are two mechanical effects: unloading rebound and perimeter rock pressure. The above deformation characteristics are the superposition effect produced by the two, and this fine assessment of the deformation of the raft foundation provides a scientific basis for formulating the deformation control countermeasuresof the crossing project. At the same time, it makes up for the blank of the double-track super-large diameter shieldtunnel down through the transportation hub project.

Assembly Induced Super-Large Red-Shifted Absorption:The Burgeoning Field of Organic Near-Infrared Materials

Supramolecular assembly of organic dye compounds with J-aggregation leads to a red-shifted absorption spectrum that greatly facilitates the construction of near-infrared(NIR)materials.A considerable improvement of the material functions requires that the absorption red-shift be larger than 100 nm,but such a super-large red-shift is challenging,and the rules leading to the super-large red-shifted absorption is still not explicit.In this review,we focused on those J-aggregated organic dye materials with super-large red-shifted absorption.The nature of the super-large red-shift is originated fromthe intermolecular charge transfer between neighboring chromophores.The super-large red-shift can be obtained by tuning either the molecular structure or kinetic assembly process in a delicate manner.Materials with super-large red-shifted absorption have been successfully applied to biological imaging,phototherapy,electronic devices,and solar cells,and show great potential in many other fields.The elaboration of assembly induced super-large red-shifted absorption is promising for design of supramolecular NIR materials with tuned structures,enhanced functionalities,and a wide array of applications.

A Super-large Aluminum Mine Discovered In Henan, With Estimated Resource Of 120 Million Tons

On March,11,according to the information from Luoyang Natural Resources and Planning Bureau,with the deepening of strategic cooperation between Luoyang and Bureau of Geology and Mineral Resources of Henan Province,great achievements have been made in prospecting,specifically in tungstenmolybdenum mine,silver mine and lead-zinc mine.These performances not only contributes to the construction of“Resource Luoyang”but also provides strong support for economic development in Luoyang.