Deep Underground Science and Engineering最新文献

{"title":"Research on in situ stress inversion of deep-buried tunnel based on pressure/tension axis mechanism and geological structure","authors":"Guanfu Chen,&nbsp;Xiaoli Liu,&nbsp;Danqing Song","doi":"10.1002/dug2.12025","DOIUrl":"https://doi.org/10.1002/dug2.12025","url":null,"abstract":"<p>The investigation of the in situ stress distribution has always been a key condition for engineering design of deep tunnels and analysis of surrounding rock stability. In this paper, a comprehensive judgment method coupled with pressure/tension (P/T) axis mechanism and geological structure is proposed to invert the in situ stress in the Duoxiongla tunnel in Tibet. In the process of TBM tunnel excavation, 3887 groups of microseismic events were collected by means of microseismic monitoring technology. By studying the temporal and spatial distribution of 3887 groups of microseismic events, 42 groups of microseismic data were selected for in situ stress inversion. Then the focal mechanisms of 42 groups of microseisms were inverted. Combined with the analysis of the previous geological survey, the inversion results of the in situ stress were analyzed. According to the focal mechanism of the tunnel area, the linear in situ stress inversion method was used to invert the in situ stress in the source area. Finally, according to the PTGS (pressure/tension axis mechanism and geological structure) comprehensive judgment method proposed in this paper, the in situ stress of the tunnel microseismic region was determined. The results show that there are mainly three groups of fissures and joint surfaces in the tunnel area, and the in situ stress is dominated by the horizontal tectonic stress; the main driving force of the rupture surface in the excavation process of Duoxiongla tunnel is the horizontal tectonic stress; the distribution of the maximum and minimum principal stress obtained by the inversion is consistent with the distribution of the P/T axis; combined with the linear in situ stress inversion method and the comprehensive judgment of PTGS, the azimuth and dip angles of the three principal stresses are finally determined as N90.71°E, 4.06°, N5.35°W, 3.06°, and N8.10W, 85.32°, respectively. The study verifies the feasibility of microseismic inversion of in situ stress.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"61-73"},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50133851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy-based analysis of seismic damage mechanism of multi-anchor piles in tunnel crossing landslide area","authors":"Hong Wei,&nbsp;Honggang Wu,&nbsp;Guojun Ren,&nbsp;Lin Tang,&nbsp;Kang Feng","doi":"10.1002/dug2.12030","DOIUrl":"https://doi.org/10.1002/dug2.12030","url":null,"abstract":"<p>To study the damage mechanism of multi-anchor piles in tunnel crossing landslide area under earthquake, the damping performance of multi-anchor piles was discussed. The energy dissipation springs were used as the optimization device of the anchor head to carry out the shaking table comparison test on the reinforced slope. The Hilbert spectrum and Hilbert marginal spectrum were proposed to analyze the seismic damage mechanism of the multi-anchor piles, and the peak Fourier spectrum amplitude (PFSA) was used to verify the effectiveness of the method. The results show that the seismic energy is concentrated in the high-frequency component (30–40 Hz) of the Hilbert spectrum and the low-frequency component (12–30 Hz) of the marginal spectrum. This indicates that they can be combined with the distribution law of the PFSA to identify the overall and local dynamic responses of the multi-anchored piles, respectively. The stretchable deformation of the energy-dissipation springs improves the coordination of the multi-anchor piles, resulting in better pile integrity. The damage mechanism of the multi-anchor piles is elucidated based on the energy method: local damage at the top and middle areas of the multi-anchor piles is mainly caused by the low-frequency component (12–30 Hz) of the marginal spectrum under the action of 0.15<i>g</i> and 0.20<i>g</i> seismic intensities. As the seismic intensity increases to 0.30<i>g</i>, the dynamic response of the slope is further amplified by the high-frequency component (30–40 Hz) of the Hilbert energy spectrum, which leads to the overall damage of the multi-anchor piles.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 3","pages":"245-261"},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50133840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Wear mechanism and life prediction of the ripper in a 9-m-diameter shield machine tunneling project of the Beijing new airport line in a sand-pebble stratum","authors":"","doi":"10.1002/dug2.12031","DOIUrl":"https://doi.org/10.1002/dug2.12031","url":null,"abstract":"<p>Jiang H, Zhu J, Zhang X, Zhang J, Li H, Meng L. Wear mechanism and life prediction of the ripper in a 9-m-diameter shield machine tunneling project of the Beijing new airport line in a sand-pebble stratum. <i>Deep Undergr Sci Eng</i>. 2022;1:65-76. doi:10.1002/dug2.12010.</p><p>There is an error in Figure 10. The corrected Figure 10 is shown below.</p><p>We apologize for this error.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 3","pages":"274"},"PeriodicalIF":0.0,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50149913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic evolution in mechanical characteristics of complex supporting structures during large section tunnel construction","authors":"Hua Jiang,&nbsp;Jianhua Mu,&nbsp;Jinxun Zhang,&nbsp;Yusheng Jiang,&nbsp;Chongyang Liu,&nbsp;Xiaoyan Zhang","doi":"10.1002/dug2.12027","DOIUrl":"10.1002/dug2.12027","url":null,"abstract":"<p>The shallow tunnelling method (STM) often uses temporary supports to divide large section tunnels into several closed or semiclosed sections so as to share the upper load. The complex support system composed of primary and temporary supports can ensure safety during tunnel construction. Based on the large section tunnel of Beijing Subway Line 12, the mechanical characteristics of support system by the double-side-drift method (DSDM) during excavation and demolition were analyzed through numerical simulation and monitoring. The study showed that the middle cave excavation was the most critical stage of the DSDM, during which the load on the supporting structure increased significantly. The temporary vertical support bore most of the new load during middle cave excavation. During the demolition stage, the load was redistributed, which caused arch settlement and section convergence. The removal of the temporary vertical support exerted the greatest impact in this process. The lateral temporary inverted arch changed from axial compression to axial tension after the middle and lower caves were excavated. Based on the mechanical characteristics of the support system, some engineering suggestions were proposed for large section tunnel construction. These research results can provide reference for the design and construction of similar large section tunnels.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"1 2","pages":"183-201"},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80501320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential triggers for large earthquakes in open-pit mines: A case study from Kuzbass, Siberia","authors":"Gevorg Kocharyan,&nbsp;Chengzhi Qi,&nbsp;Svetlana Kishkina,&nbsp;Vladimir Kulikov","doi":"10.1002/dug2.12028","DOIUrl":"10.1002/dug2.12028","url":null,"abstract":"<p>The extraction and movement of rock during mining operations is considered a possible trigger for slip along the fault. In this study, possible anthropogenic causes were analyzed for triggering the earthquake with the local magnitude of <i>M</i>_L = 6.1 (at a depth of 4 km just beneath the quarry), in the vicinity of the large coal open-pit mine in Russia. This event was the largest earthquake associated with a quarry (an open pit). A sufficiently deep occurrence of the source testified that seismic vibrations were produced in a dynamic slip along a preexisting and prestressed tectonic fault. Analytical calculations were conducted of increments of normal and shear stresses at fault planes with several dip angles at depths corresponding to the probable location of the hypocenter of the Bachat earthquake. As the results show, long-term rock excavations bring a prestressed thrust fault closer to the ultimate Coulomb strength, and stress variations at those depths may suffice to initiate a movement along the fault. By measuring seismic vibrations at different quarries and mines in Russia, the dynamic effect at the supposed depth of the source occurrence could be reliably estimated. As is shown, the ultimate anticipated dynamic deformations are noticeably lower than corresponding values produced by seismic waves of distant earthquakes in the case when the effects of dynamic triggering were observed. Accordingly, the seismic effect of explosions cannot trigger a large earthquake with deep source occurrence. Operations in open-pit mines can only bring forward the moment of an earthquake at a potentially seismogenic fault. At the same time, the numerical calculations reveal that a branching network of underground tunnels located at several horizons can noticeably reduce the effective shear modulus of the host rock. This effect can even provoke a dynamic movement at a previously aseismic fault.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"1 2","pages":"101-115"},"PeriodicalIF":0.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73746810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grouting theories and technologies for the reinforcement of fractured rocks surrounding deep roadways","authors":"Hongpu Kang,&nbsp;Wenzhou Li,&nbsp;Fuqiang Gao,&nbsp;Jianwei Yang","doi":"10.1002/dug2.12026","DOIUrl":"https://doi.org/10.1002/dug2.12026","url":null,"abstract":"<p>Grouting is an effective method to improve the integrity and stability of fractured rocks that surround deep roadways. After years of research and practice, various theories and a complete set of grouting technologies for deep roadways with fractured rocks have been developed and are widely applied in Chinese coal mining production. This paper systematically summarizes and analyzes the research results concerning the theory, design, materials, processes, and equipment for the grouting and reinforcement of fractured rocks surrounding deep roadways. Specifically, in terms of grouting methods, pregrouting, grouting-while-excavation, and postgrouting methods are explored; in terms of grouting theory, backfill grouting, compaction grouting, infiltration grouting, and fracture grouting theories are studied. In addition, this paper also studies grouting borehole arrangement, water-cement ratio, grouting pressure, grouting volume, grout diffusion radius, and other grouting parameters and their determination methods. On this basis, this paper explores the physical and mechanical properties of organic and organic-inorganic composite grouting materials, and assess grouting reinforcement quality testing methods and instruments. Taken as the field cases, the application of pregrouting in front of heading faces, grouting-while-excavation, and postgrouting in the Kouzidong coal mine are then introduced, and the effects of the grouting reinforcements are evaluated. This paper proposes a development direction for grouting technology based on problems existing in the grouting reinforcement of fractured rocks surrounding deep roadways.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"2-19"},"PeriodicalIF":0.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50151259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation characteristics and novel strain criteria of strainbursts induced by low-frequency cyclic disturbance","authors":"Lihua Hu,&nbsp;Minghe Ju,&nbsp;Peng Zhao,&nbsp;Xiaozhao Li","doi":"10.1002/dug2.12029","DOIUrl":"https://doi.org/10.1002/dug2.12029","url":null,"abstract":"<p>Strainbursts induced by cyclic disturbance with low frequency (termed as cyclic-induced strainbursts) are major dynamic disasters during deep excavation and mining. There is currently no quantitative criterion available for the prediction of such disastrous events. In this study, based on true triaxial experiments, we analyzed the deformation characteristics, established two novel strain criteria for the cyclic-induced strainbursts, and explained the physical meaning of these criteria. Characteristic strains for the cyclic-induced strainbursts were defined, including the control strain <i>ε</i>_ctr, the strain caused by the combined dynamic and static loading <i>ε</i>_sd, and the ultimate strain <i>ε</i>_u after strainbursts. As indicated by the results, the deformation evolution of the cyclic-induced strainbursts shows remarkable fatigue characteristics, which resemble that of rock subjected to cyclic loading and unloading. In other words, there are three stages during deformation evolution, namely, initial rapid growth, uniform velocity growth after several periods of disturbance, and sudden sharp growth preceding the burst. The ultimate strain <i>ε</i>_u is insensitive to the tangential static stress and disturbance amplitude, but it changes nonlinearly with disturbance frequency. From the perspective of deformation, the occurrence of a cyclic-induced strainburst is controlled by the control strain <i>ε</i>_ctr. Thus, a control strain criterion is proposed; that is, when the stain <i>ε</i>_sd is larger than the control strain <i>ε</i>_ctr, a strainburst will be induced by cyclic disturbance. Moreover, based on the statistical results, a strain ratio criterion is proposed; that is, when the strain ratio <i>ε</i>_sd/<i>ε</i>_u is greater than 30%, a cyclic-induced strainburst will be induced.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"52-60"},"PeriodicalIF":0.0,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50132100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of joints on microwave fracturing of the Bukit Timah granite using an open-ended antenna","authors":"Zhongjun Ma,&nbsp;Yanlong Zheng,&nbsp;Lei He,&nbsp;Jianchun Li","doi":"10.1002/dug2.12024","DOIUrl":"10.1002/dug2.12024","url":null,"abstract":"<p>Microwave fracturing of rocks before mechanical breakage could improve the performance of mechanical excavators and reduce environmental impacts. Previous research focused on the microwave fracturing of intact rock blocks. By using an open-ended antenna, this paper investigates the effect of pre-existing joints on the microwave fracturing of the Singapore Bukit Timah granite blocks. The results show that the specimens are weakened in the manners of cracking, spalling, melting, or a combination of them. The crack number and the total crack length produced by microwave treatment of jointed rock blocks are slightly smaller than those in the intact rock blocks. The interaction between joints and microwave-induced cracks can be summarized into the following four patterns: (1) microwave-induced cracks become arrested so that the crack propagation is terminated; (2) microwave-induced cracks penetrate the joints and continue to propagate; (3) microwave-induced cracks become deflected along the joints; and (4) microwave-induced cracks propagate forward following the joints. The smaller the approach angle between the microwave-induced crack and the pre-existing joint is, the more microwave-induced cracks tend to be arrested at the joint. Increasing the approach angle between the microwave-induced crack and the joint can increase the chance of microwave-induced crack penetrating the joint. The results also show that the smaller the distance is between the microwave radiation point and the joint, the easier it is for microwave-induced cracks to penetrate the joints; otherwise, the microwave-induced crack is more likely to be arrested at the pre-existing joint.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"1 2","pages":"138-147"},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81040299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coal rock image recognition method based on improved CLBP and receptive field theory","authors":"Chuanmeng Sun,&nbsp;Ruijia Xu,&nbsp;Chong Wang,&nbsp;Tiehua Ma,&nbsp;Jiaxin Chen","doi":"10.1002/dug2.12023","DOIUrl":"10.1002/dug2.12023","url":null,"abstract":"<p>Rapid coal-rock identification is one of the key technologies for intelligent and unmanned coal mining. Currently, the existing image recognition algorithms cannot satisfy practical needs in terms of recognition speed and accuracy. In view of the evident differences between coal and rock in visual attributes such as color, gloss and texture, the complete local binary pattern (CLBP) image feature descriptor is introduced for coal and rock image recognition. Given that the original algorithm oversimplifies local texture features by ignoring imaging information from higher-order pixels and the concave and convex areas between adjacent sampling points, this paper proposes a higher-order differential median CLBP image feature descriptor to replace the original CLBP center pixel gray with a local gray median, and replace the binary differential with a second-order differential. Meanwhile, for the high dimensionality of CLBP descriptor histogram and feature redundancy, deep learning perceptual field theory is introduced to realize data nonlinear dimensionality reduction and deep feature extraction. With relevant experiments conducted, the following conclusion can be drawn: (1) Compared with that of the original CLBP, the recognition accuracy of the improved CLBP algorithm is greatly improved and finally stabilized above 94.3% under strong noise interference; (2) Compared with that of the original CLBP model, the single image recognition time of the coal rock image recognition model fusing the improved CLBP and the receptive field theory is 0.0035 s, a reduction of 71.0%; compared with the improved CLBP model (without the fusion of receptive field theory), it can shorten the recognition time by 97.0%, but the accuracy rate still maintains more than 98.5%. The method offers a valuable technical reference for the fields of mineral development and deep mining.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"1 2","pages":"165-173"},"PeriodicalIF":0.0,"publicationDate":"2022-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90241676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeological feasibility of mine water deep geological storage in Baotashan coarse sandstone: A case study in Ordos Basin","authors":"Ge Chen,&nbsp;Yajun Sun,&nbsp;Zhimin Xu,&nbsp;Xin Li","doi":"10.1002/dug2.12022","DOIUrl":"10.1002/dug2.12022","url":null,"abstract":"<p>For the sake of mine water drainage and sustainable groundwater protection, the new approach of mine water deep geological storage (MWDGS) is highly necessary to save water resources in the semi-arid region of China. However, up to now, little academic research has been done on mine water geological storage. Given this situation, the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone (BCS) of Jurassic measure in Ordos Basin. The results show that the white-gray BCS with a fragile skeleton of quartz (41.4%), feldspar (21.1%), and clay minerals (16.4%) provides the potential variable-void for mine water; and its hydro-chemical type of BCS aquifer is CO₃-Na and Cl-Na. As the burial depth increases, the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition. The lab test shows that the pores whose diameter is over 10 μm could be treated as the main storage of mine water; and the effective porosity varies from 1.36% to 3.46%. When mine water is injected, the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201% soluble solids would be dissolved. Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability. Under the condition of nonhydraulic fracturing during continuous storage, the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics (TPROGS) shows that the capacity of BCS aquifer is 0.455 to 1.226 Mm³ for 1 km² in the study area. The simulation shows that the groundwater mound in well-scale and mine-scale would be formed. The groundwater quality characteristics of “Three Zone” would occur around and gradually drop to approximate the original brine within 10 years. The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"1 2","pages":"148-164"},"PeriodicalIF":0.0,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84508095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}