scholarly journals Study of Crater in the Gobi Desert Induced by Ground Explosion of Large Amounts of TNT Explosive up to 10 Tons

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Rongzheng Xu ◽  
Li Chen ◽  
Yuzhou Zheng ◽  
Zhan Li ◽  
Mingjin Cao ◽  
...  
Keyword(s):  
Conversion Coefficient ◽  
Near Field ◽  
Ground Surface ◽  
Failure Criteria ◽  
Gobi Desert ◽  
Large Weight ◽  
Fine Mesh ◽  
Contact Explosion ◽  
Protective Strategy ◽  
Sand And Gravel

Explosion craters on the ground surface induced by contact or near-field explosions have important implications, which can be used to assess blast consequences, guide the design of the explosion, or develop a protective strategy. In this study, to understand the crater characteristics induced by the contact explosion of large weight explosives, four field contact explosion tests were conducted on the surface of the Gobi Desert with large TNT charge weights of 1 ton, 3 tons, and 10 tons (test conducted twice). Cratering on the ground surface generated by large amounts of explosives was measured and evaluated, including the shape, depth, and diameter. A fine-mesh numerical model was developed and validated on the AUTODYN software platform, and a detailed parametric study was performed on the resulting craters. The effects of sand and gravel density, initiation method, shear modulus, and failure criteria were analyzed and discussed. An energy conversion coefficient was determined, and the corresponding theoretical equations were derived to predict the dimensions of the craters resulting from the large weight contact explosion. The calculated cratering characteristics were consistent with previous data and hence can be used in future engineering applications.

A Note on Radionuclide Transport by Gas Bubbles

1996 ◽  
Vol 465 ◽  
Author(s):  
Ivars Neretnieks ◽  
Märta-Lena Ernstson
Keyword(s):  
Carrying Capacity ◽  
Colloidal Particles ◽  
Spent Nuclear Fuel ◽  
Near Field ◽  
Ground Surface ◽  
Gas Bubbles ◽  
Escape Rate ◽  
Fuel Gas ◽  
Buffer Material ◽  
Bubble Transport

ABSTRACTIn a repository for spent nuclear fuel, gas generated by corrosion of the iron in the canister may form small bubbles that will escape and rise to the ground surface. Colloidal particles may attach to the surface of the bubbles and be carried by them. If the colloids are supplied by the montmorillonite clay of the buffer material surrounding the canister, the clay can be carried away. Nuclides sorbed in the clay can be carried with the bubbles. We have estimated the carrying capacity of the gas of the clay particles and the escape rate of nuclides carried by the gas bubbles. The latter is also compared to the escape rate by the conventional escape mechanisms from the near field. We have further estimated the detachment of the nuclides from the clay and their sorption onto the fracture surfaces of the rock as well as their uptake by diffusion into the rock matrix along the bubble transport paths.The present paper is speculative and uses some hypothetical assumptions. Although the processes that are modelled are known to exist there is not enough known of several of them to quantify them accurately. The carrying capacity of the gas used in the calculations is an upper bound and probably very much exaggerated. Even so, the consequences are minor for the release of radionuclides.

Numerical analysis of axial load effects on RC bridge columns under blast loading

2020 ◽  
pp. 136943322097944
Author(s):  
Sujing Yuan ◽  
Hong Hao ◽  
Zhouhong Zong ◽  
Jun Li
Keyword(s):  
Axial Load ◽  
Near Field ◽  
Dynamic Performance ◽  
Compressive Load ◽  
Axial Loading ◽  
Blast Loading ◽  
Bridge Columns ◽  
Load Effect ◽  
Contact Explosion ◽  
Rc Bridge Columns

Blast load and its effects on transportation infrastructure especially bridge structures have received considerable attention in recent years. The RC bridge columns are considered as the most critical structural members because their failure leads to collapse of the bridge. Although RC bridge columns are typical axial load-carrying components, the studies on blast-resistant capacity of RC bridge columns usually neglect the axial load effect since it is commonly assumed that neglecting the axial load leads to conservative predictions of column responses. This assumption is true when column failure is governed by flexural response since axial compressive load generates a prestress in column which compensates concrete tensile stress induced by bending response. When subjected to blast loads, column response however could be governed by shear response. In this case neglecting axial loading effect does not necessarily lead to conservative predictions of column responses. In this study, high-fidelity finite element (FE) models for both non-contact explosion and contact explosion were developed in LS-DYNA. The FE models were validated with field blast test data. Subsequently, intensive simulations of the RC bridge columns with and without axial load subjected to a wider range of blast loading scenarios, including far-field, near-field and contact explosion were conducted. The influence of axial load on the dynamic performance of RC bridge columns corresponding to different blast loading scenarios was discussed.

scholarly journals Impact of Gobi desert dust on aerosol chemistry of Xi'an, inland China during spring 2009: differences in composition and size distribution between the urban ground surface and the mountain atmosphere

2012 ◽  
Vol 12 (8) ◽  
pp. 21355-21397 ◽  
Author(s):  
G. H. Wang ◽  
B. H. Zhou ◽  
C. L. Cheng ◽  
J. J. Cao ◽  
J. J. Meng ◽  
...  
Keyword(s):  
Size Distribution ◽  
Fine Particles ◽  
Major Ions ◽  
Ground Surface ◽  
Sampling Period ◽  
Water Soluble ◽  
Gobi Desert ◽  
Urban Air ◽  
Coarse Particles ◽  
Aerosol Chemistry

Abstract. Composition and size distribution of atmospheric aerosols from Xi'an city (~400 m, altitude) in inland China during the spring of 2009 including a massive dust event on 24 April were measured and compared with a parallel measurement at the summit (2060 m, altitude) of Mt. Hua, an alpine site nearby Xi'an. EC, OC and major ions in the city were 2–22 times higher than those on the mountaintop during the whole sampling period. Sulfate was the highest species in the nonevent time in Xi'an and Mt. Hua, followed by nitrate, OC and NH4+. In contrast, OC was the most abundant in the event at both sites, followed by sulfate, nitrate and Ca2+. Compared to those on the urban ground surface aerosols in the elevated troposphere over Mt. Hua contain more sulfate and less nitrate, because HNO3 is formed faster than H2SO4 and thus long-range transport of HNO3 is less significant than that of H2SO4. An increased water-soluble organic nitrogen (WSON) was observed for the dust samples from Xi'an, indicating a significant deposition of anthropogenic WSON onto dust and/or an input of biogenic WSON from Gobi desert. As far as we know, it is for the first time to perform a simultaneous observation of aerosol chemistry between the ground surface and the free troposphere in inland East Asia. Our results showed that fine particles are more acidic on the mountaintop than on the urban ground surface in the nonevent, mainly due to continuous oxidation of SO2 to produce H2SO4 during the transport from lowland areas to the alpine atmosphere. However, we found the urban fine particles became more acidic in the event than in the nonevent, in contrast to the mountain atmosphere, where fine particles were less acidic when dust was present. The opposite changes in acidity of fine particles at both sites during the event are mostly caused by enhanced heterogeneous formation of nitrate onto dust in the urban air and decreased formation of nitrate in the mountain troposphere. In comparison to those during the nonevent Cl− and NO3− in the urban air during the event significantly shifted toward coarse particles. Such redistributions were further pronounced on the mountaintop when dust was present, resulting in both ions almost entirely staying in coarse particles. On the contrary, no significant spatial difference in size distribution of SO42− was found between the urban ground surface and the mountain atmosphere, dominating in the fine mode (<2.1 μm) during the nonevent and comparably distributing in the fine (<2.1 μm) and coarse (>2.1 μm) modes during the event.

The Geotechnical Design of the Townline Road–Rail Tunnel

1971 ◽  
Vol 8 (2) ◽  
pp. 299-314 ◽  
Author(s):  
Robert J. Conlon ◽  
Roy G. Tanner ◽  
Keith L. Coldwell
Keyword(s):  
Shear Strength ◽  
Ground Surface ◽  
Failure Surface ◽  
Tunnel Structure ◽  
Flat Portion ◽  
Geotechnical Design ◽  
Critical Layers ◽  
The Stability ◽  
Sand And Gravel ◽  
The City

The Townline road–rail tunnel is being constructed beneath the relocation of the Welland canal to the east of the city of Welland. Construction is by opencut and cut-and-cover through up to 80 ft (24 m) of lacustrine clays and clay tills. The lower stratified zone in the lacustrine clays has a minimum shear strength parallel to the bedding in some critical layers. Slope stability studies involved detailed sampling and testing, including block samples and 5-in.(13-cm) tube samples, and correlations with previous landslides in the area. These studies demonstrate that the mechanism of landslides in this stratigraphy involves a long flat portion of failure surface in the lower stratified zone, and that the shear strength available along this portion of the failure surface is consistent with the minimum shear strengths measured parallel to the bedding. Slopes as flat as 8.5:1 are required in areas which combine the deepest cuts and deepest overburden deposits.The concrete tunnel structure is being founded on bedrock consisting of a gypsiferous dolomite containing thick layers and lenses of essentially pure gypsum. Within the upper broken zone of the bedrock and some thin pervious lenses of sand and gravel immediately overlying the bedrock is an aquifer zone which is a major source of groundwater. Prior to construction, the piezometric level in this aquifer was approximately at the ground surface. The groundwater level in the aquifer zone had to be drawn down during construction and must be controlled throughout the life of the structure to provide for the stability of the overburden slopes. At the same time, the gypsum beneath the tunnel structure will be maintained intact by a drainage scheme which essentially isolates the rock beneath the structure from future groundwater flow, thereby precluding any significant solutioning of the gypsum.

scholarly journals Impact of Gobi desert dust on aerosol chemistry of Xi'an, inland China during spring 2009: differences in composition and size distribution between the urban ground surface and the mountain atmosphere

2013 ◽  
Vol 13 (2) ◽  
pp. 819-835 ◽  
Author(s):  
G. H. Wang ◽  
B. H. Zhou ◽  
C. L. Cheng ◽  
J. J. Cao ◽  
J. J. Li ◽  
...  
Keyword(s):  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Major Ions ◽  
Heterogeneous Reaction ◽  
Ground Surface ◽  
Sampling Period ◽  
Gobi Desert ◽  
Coarse Particles ◽  
Dust Event

Abstract. Composition and size distribution of atmospheric aerosols from Xi'an city (~400 m, altitude) in inland China during the spring of 2009 including a massive dust event on 24 April were measured and compared with a parallel measurement at the summit (2060 m, altitude) of Mt. Hua, an alpine site nearby Xi'an. EC (elemental carbon), OC (organic carbon) and major ions in the city were 2–22 times higher than those on the mountaintop during the whole sampling period. Compared to that in the non-dust period a sharp increase in OC was observed at both sites during the dust period, which was mainly caused by an input of biogenic organics from the Gobi desert. However, adsorption/heterogeneous reaction of gaseous organics with dust was another important source of OC in the urban, contributing 22% of OC in the dust event. In contrast to the mountain atmosphere where fine particles were less acidic when dust was present, the urban fine particles became more acidic in the dust event than in the non-dust event, mainly due to enhanced heterogeneous formation of nitrate and diluted NH3. Cl− and NO3− in the urban air during the dust event significantly shifted toward coarse particles. Such redistributions were further pronounced on the mountaintop when dust was present, resulting in both ions almost entirely staying in coarse particles. On the contrary, no significant spatial difference in size distribution of SO42− was found between the urban ground surface and the mountain atmosphere, which dominated in the fine mode (<2.1 μm) during the nonevent and comparably distributed in the fine (<2.1 μm) and coarse (>2.1 μm) modes during the dust event.

scholarly journals KARAKTERISTIK ENDAPAN SEDIMEN PANTAI TERHADAP PENGARUH LIQUIFAKSI DI KAWASAN PESISIR PANGANDARAN DAN SEKITARNYA, KABUPATEN CIAMIS, JAWA BARAT

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Kris Budiono ◽  
Purnomo Raharjo
Keyword(s):  
Void Ratio ◽  
Ground Surface ◽  
Soil Mechanic ◽  
Geological Hazards ◽  
Survey Area ◽  
Ground Acceleration ◽  
Richter Scale ◽  
Simplified Procedure ◽  
Sand And Gravel ◽  
Critical Void

Liquifaksi adalah salah satu bencana geologi yang berhubungan dengan kegempaan, dimana tekanan pori dalam tanah atau sedimen mengalami peningkatan akibat getaran, sehingga mengakibatkan aliran air ke arah permukaan tanah. Liquifaksi umumnya terjadi pada dataran rendah termasuk kawasan pesisir. Daerah penelitian yang terletak di sekitar pantai Pangandaran dan Parigi terdiri dari endapan lempung, lanau, pasir dan kerikil yang bersifat lepas dan jenuh air, secara regional sering dipengaruhi oleh kekuatan gempa antara 5,5 – 6 skala Richter dengan percepatan tanah antara 150 – 200 mgal. Kondisi seperti ini apabila terjadi gempa sangat memungkinkan untuk terjadi liquifaksi. Berdasarkan hasil perhitungan secara kuantitatif nisbah pori kritis, tidak semua lokasi penelitian akan mengalami liquifaksi pada percepatan permukaan 150 – 200 mgal. Berdasarkan nilai tumbukan SPT yang dipakai untuk analisis “simplified procedure”, daerah penelitian secara umum relatif kecil terhadap bahaya liquifaksi. Namun demikian berdasarkan korelasi antara sifat mekanik tanah dengan nilai SPT, pada kedalaman 0 – 8 m terdapat lapisan sedimen yang cukup rentan terhadap liquifaksi. Kata kunci: Liquifaksi,sedimen pantai,Pangandaran Liquefaction is one of many geological hazards related to an earthquake, where the void ratio pressure in soil or sediment will increase due to the vibration, that causing water flow up to the ground surface. Generally liquefaction is occurred in the low lying areas including coastal zone. The survey area located in the Pangandaran and Parigi coasts, is consisted of clay, silt, sand and gravel, of loose and saturated properties, generally is frequently influenced by 5,5 – 6 Richter scale of earthquake strength with the ground acceleration between 150 – 200 mgal. The liquefaction will be occurred in this condition if there is an earthquake. Based on the quantitatively calculation of critical void ratio, the liquefaction at ground acceleration of 150 – 200 mgal will not be occurred at all of the survey area. Based on the number of blows of SPT which is used for simplified procedure analysis, it shows that the study area is less influenced by the liquefaction. Nevertheless , based on the correlation between soil mechanic properties and SPT value, there is potential liquefiable sediments layer between the depth of 0 – 8 meters. Key words: liquefaction, coastal sediment, Pangandaran

scholarly journals Damage Characteristics of Polymer Plates under the Impact of the Near-Field and Contact Underwater Explosion

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shucan Liu ◽  
Xiaohua Zhao ◽  
Hongyuan Fang ◽  
Xueming Du ◽  
Binghan Xue
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Underwater Explosion ◽  
Damage Mode ◽  
Distribution Characteristics ◽  
Emulsion Explosive ◽  
Damage Characteristics ◽  
Contact Explosion ◽  
Spatial Distribution Characteristics ◽  
The Impact

In order to study the damage characteristics of polymer plates under the impact of the underwater explosion, the underwater contact and near-field explosion tests of polymer plates were conducted using different explosive quantities. In this paper, eight polymer plates with the size of 500 mm × 500 mm × 60 mm were made, and eight groups of explosion tests were carried out by using the rock emulsion explosive and nonconductive detonators. The damage modes and spatial distribution characteristics of the polymer plate generated by the underwater contact and near-field explosion impact with different explosive quantities are compared and analyzed. In addition, the characteristics of the shock wave propagation in the plates are investigated. It can be observed that the main damage mode of polymer plate is overall damage under the contact underwater explosion. For the near-field explosion, the main damage mode changes to overall failure, and the damage of contact explosion to polymer plate is greater than that of underwater near-field explosion. The polymer plate can reduce and delay the shock wave effectively, but the effect decreases with the increase of explosive quantity in the underwater contact explosion.

scholarly journals Fragility Analysis of Structural Pounding Between Adjacent Structures Arranged in Series With Various Alignment Configurations Under Near-field Earthquakes

2022 ◽  
Author(s):  
Fahimeh Ebrahimiyan ◽  
Mohammad Ali Hadianfard ◽  
Hosein Naderpour ◽  
Robert Jankowski
Keyword(s):  
Fragility Curves ◽  
Near Field ◽  
Limit State ◽  
Failure Criteria ◽  
Structural Performance ◽  
Structural Pounding ◽  
Critical Situation ◽  
Adjacent Structures ◽  
Moment Resisting ◽  
In Series

Abstract A major cause of local to total damages is related to structural pounding in a large number of past earthquakes. In general, these collisions take place as a result of differences in the dynamic characteristics of the colliding structures. To acquire a better perception of the behavior of structures, in this paper, three structures featuring different heights are modeled in series and with various configurations next to each other in OpenSees. To determine the collision effects of the structures, three different configurations of 4-, 8- and 12-story adjacent reinforced concrete special moment resisting frames were considered. Then, by conducting an incremental dynamic analysis, their structural seismic limit state capacities were assessed via 20 near-field record subsets recommended by FEMA-P695. At last, for the above adjacent buildings with various separation distances and configurations, the fragility curves were determined, and the probability of exceedance from the primary Hazus-MH failure criteria was estimated. In addition, the results were compared with those obtained when this phenomenon did not take place for buildings to have a better perception of the pounding phenomenon. The results of the analyses show that arranging adjacent structures in series greatly affects the collapse capacities of the colliding structures. In addition, in the case when the shorter structure is placed in the middle of two taller structures, it results in the most critical situation among all configurations, and in this case, a higher reduction is observed in the structural performance levels.

Dynamic Response of Pile Groups under Vertical Forces in Saturated Soil

2011 ◽  
Vol 261-263 ◽  
pp. 1499-1504
Author(s):  
Yuan Yi Zhao ◽  
Zhou Hong Tao
Keyword(s):  
Permeability Coefficient ◽  
Near Field ◽  
Ground Surface ◽  
Pile Group ◽  
Dynamic Force ◽  
Pile Groups ◽  
Propagation Equation ◽  
Soil System ◽  
Different Types ◽  
Ground Surface Movement

Based on Biot’s wave propagation equation and boundary conditions, this paper builds up pile group and soil system used for calculation in 3 dimension models, though mass conservative and motion equation. The results of ground surface movement are obtained under the effect of vertical dynamic force though Newmark direct integration. Compared with the measured results, the numerical outcomes conform accurately. The calculating results show that vibration of ground surface can be affected by several parameters such as soils’ possion ratio, permeability coefficient, different types of pile groups and so on. Different factors have different effects on ground’s surface vibration in both far field and near field.

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