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Foundation Pit Leakage Detection Method Based on Electrical Resistivity Imaging Technology
Cai Kejian,
Yin Yabin,
Liaozhi,
Ding Yueshuang,
Wu Yuhao
Issue:
Volume 7, Issue 4, August 2018
Pages:
144-150
Received:
21 May 2018
Accepted:
7 June 2018
Published:
29 June 2018
Abstract: With the continuous development of city construction and development of underground engineering, increasingly large scale, all kinds of super large and deep foundation pit appear constantly, especially in soft soil and high groundwater level area. Due to the leakage problem of the foundation pit engineering, accidents happen. Pit leakage is a common construction defect of construction waterproof curtain, therefore, it is necessary to detect the leakage situation of the foundation pit supporting system in advance, so that the leakage area is treated and prevented in time. In the foundation pit engineering, it is often used to observe the water level changes inside and outside the foundation pit to deduce the approximate area of the foundation pit leakage. Therefore, the use of geophysical methods for leakage detection research has become a breakthrough in solving the problem of leakage of foundation pit. In this paper, variation of groundwater flow around the foundation pit line is discussed when there is leakage of foundation pit system, for instance, leaking water aggregation, intensive regional seepage resistance, resulting in low resistivity of leakage area around the foundation pit of low resistivity. Based on the resistivity imaging technique, the method for detecting the leakage of the foundation pit by detecting the change of resistivity of soil around foundation pit before and after dewatering is presented. It is through two engineering examples show that this method can detect the pit leakage detection results of three-dimensional position, detection results objectively and accurately.
Abstract: With the continuous development of city construction and development of underground engineering, increasingly large scale, all kinds of super large and deep foundation pit appear constantly, especially in soft soil and high groundwater level area. Due to the leakage problem of the foundation pit engineering, accidents happen. Pit leakage is a commo...
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Kuqa Complex Surface Area Pseudo 3D Near-Surface Modeling and Static Correction Techniques
Lyu Jingfeng,
Zhou Bingfeng,
Li Zhiliu
Issue:
Volume 7, Issue 4, August 2018
Pages:
151-157
Received:
22 May 2018
Accepted:
8 June 2018
Published:
5 July 2018
Abstract: Having been one of the key areas for hydrocarbon prospection of Tarim Oilfield Company, Kuqa Mountain in Tarim Basin has significant LVL survey, modeling difficulty and statics problems due to its diversified near-surface conditions. In this paper, the author makes an accurate analysis on the near-surface structure in the area using the uphole-constraint shallow-layer tomography LVL surface method, the pseudo 3D near-surface modeling and the comprehensive statics technology and therefore, the imaging of sections is improved, which provides a reference for the near-surface modeling and statics works in similar areas.
Abstract: Having been one of the key areas for hydrocarbon prospection of Tarim Oilfield Company, Kuqa Mountain in Tarim Basin has significant LVL survey, modeling difficulty and statics problems due to its diversified near-surface conditions. In this paper, the author makes an accurate analysis on the near-surface structure in the area using the uphole-cons...
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Identification of Diagenetic Facies Based on Diagenetic Process: An Example from Paleogene Lake Sediment Sandstone in Bozhong X Oilfield
Qian Wendao,
Yin Taiju,
Sun Shaochuan,
Zhang Changmin,
Hou Guowei,
He Miao,
Xia Min
Issue:
Volume 7, Issue 4, August 2018
Pages:
158-165
Received:
3 June 2018
Accepted:
19 June 2018
Published:
7 July 2018
Abstract: Based on diagenetic evolution, reservoir diagenetic facies evolution was restored in burial history through quantitatively calculating the original porosity reconstructed by compaction, cementation and dissolution using core measurement data. The essence of this method was illustrated and its effectiveness was demonstrated using Paleogene lake sediment sandstone in Bozhong X oilfield, Bohai Bay Basin, China. Because diagenetic field changes as the structure depth increases or decreases and acts on deposition, diagenetic facies can be significantly different in different geological period. The Ed1 reservoir has experienced such an evolutionary process of W-Com_W-Cla-C_M-Car-C to M-Com_M-Clay-C_W-Qua-C_W-Fel-D_W-Car-D to M-Com_M-Cla-C_W-Qua-C_W-Fel-D_W-Car-D, while the Ed2 , the Ed3 and the Es1 are W-Com_W-Cla-C to M-Com_M-Cla-C-S-Com_S-Clay-C_W-Qua-C_W-Fel-D to S-Com_S-Cla-C_W-Qua-C_M-Fel-D, M-Com_W-Cla-C_W-Qua-C_W-Fel-D to M-Com_M-Cla-C_W-Qua-C_W-Fel-D to S-Com_M-Clay-C_W-Qua-C_S-Fel-D to S-Com_S-Clay-C_M-Qua-C_S-Fel-D and M-Com_W-Cla-C_W-Car-C to M-Com_M-Cla-C_W-Car-C_M-Fel-D_W-Car-D to M-Com_M-Clay-C_S-Fel-D_M-Car-D to S-Com_M-Cla-C _S-Fel-D_ M-Car-D respectively. Through this study, the reason for the dynamic change of sand body in the diagenetic field and the anisotropy of the reservoir are revealed.
Abstract: Based on diagenetic evolution, reservoir diagenetic facies evolution was restored in burial history through quantitatively calculating the original porosity reconstructed by compaction, cementation and dissolution using core measurement data. The essence of this method was illustrated and its effectiveness was demonstrated using Paleogene lake sedi...
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Numerical Simulation of Diagenetic Stage in Sandstone Reservoir of Huagang Formation in Xihu Sag
Xia Min,
Yin Taiju,
Qian Wendao,
Zhang Changmin,
Hou Guowei,
He Miao
Issue:
Volume 7, Issue 4, August 2018
Pages:
166-174
Received:
20 June 2018
Accepted:
3 July 2018
Published:
27 July 2018
Abstract: To predict distribution of diagenetic stages of Xihu Sag Huagang Formation sandstone reservoir and secondary pore development zone, and research original pore reservation and secondary pore increase and decrease in reservoir evolution process, combining traditional diagenesis research and numerical simulation technique, and based on interaction model and effect model, this paper establishes a aggregative model on numerical simulation of diagenetic stages. In diagenesis simulation process, based on process response principle, and restricted by current diagenetic stage distribution and type, diagenetic stage distribution and type of reservoir during geological historical evolution period is back stripped through diagenetic temperature. Taking single well diagenetic stage data as constraint condition, and combining with research area burial history, ground temperature history, and diagenetic stage division basis, and scheme, plane distribution of diagenetic stages of the whole research area during each geological historical period is finally obtained.
Abstract: To predict distribution of diagenetic stages of Xihu Sag Huagang Formation sandstone reservoir and secondary pore development zone, and research original pore reservation and secondary pore increase and decrease in reservoir evolution process, combining traditional diagenesis research and numerical simulation technique, and based on interaction mod...
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Characteristics of Convective Storm Top Altitudes in Summer over the Tibetan Plateau by GPM
Cai Hongke,
Sun Yi,
Chen Quanliang
Issue:
Volume 7, Issue 4, August 2018
Pages:
175-182
Received:
19 July 2018
Accepted:
3 August 2018
Published:
29 August 2018
Abstract: To have a clear understanding of the convective precipitation over the Tibetan Plateau (TP) and its surrounding regions, this research systematically studied characteristics of distribution of convective storm top altitudes over the Tibetan Plateau and its surrounding regions by using the level-2 orbital data obtained by the Global Precipitation Mission (GPM) Dual-frequency Precipitation Radar (DPR). The following conclusions are drawn in this study. (1) Because of the development of Asia summer monsoon, the number of samples of precipitation with storm top altitude above 10 km increases gradually from June to August, and all the samples of precipitation diminishes with the increases of altitude. That is, the higher the storm top altitude, the less the frequency of precipitation. (2) The deep convection frequency above 10 km altitude over the Tibetan Plateau and its surrounding regions is less than 0.8%. The deep convection frequency above 14 km is obviously less than the 10 km deep convection, not exceeding 0.2%. (3) With the increase of convective storm top altitude, the proportion of corresponding deep convection decreases exponentially. The contribution of convective precipitation to total precipitation is consistent with the contribution of convective precipitation frequency to total precipitation frequency, and the both area fractions of them decrease rapidly with the increases of the contribution. Besides, both of the two maximum contributions are below 40%. (4) The storm top altitude and surface rain rate of convective precipitation are the lowest in June and the highest in August. Furthermore, the storm top altitude over the TP rises slowly from the western part of the plateau to the eastern part, and the rain rate shows a significant gradient change with the increases of height. Below 6 km altitude, the maximum value of rain rate can reach 8 mm/h, but the precipitation intensity reduce to 4 mm/h when the altitude is above 6 km.
Abstract: To have a clear understanding of the convective precipitation over the Tibetan Plateau (TP) and its surrounding regions, this research systematically studied characteristics of distribution of convective storm top altitudes over the Tibetan Plateau and its surrounding regions by using the level-2 orbital data obtained by the Global Precipitation Mi...
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Predicting of the Seismogram and Accelerogram of Strong Motions of the Soil for an Earthquake Model Considered as an Instantaneous Rupture of the Earth’s Surface
Issue:
Volume 7, Issue 4, August 2018
Pages:
183-201
Received:
4 May 2018
Accepted:
12 July 2018
Published:
30 August 2018
Abstract: Problems of the prediction of displacement and acceleration values for strong soil displacements are considered for the case where an earthquake is regarded as an instantaneous mechanical rupture of the Earth’s surface. We have attempted to develop, based on recent concepts of earthquake generation process, simplified theoretical methods for the quantitative prediction of soil displacement parameters during strong earthquakes. As an illustrative example, we consider an earthquake originating as a consequence of relative displacements of suddenly ruptured blocks in a horizontal direction with a given initial velocity. An empirical relationship between soil particle motion velocity near the rupture and at a certain distance from it, on one hand, and the earthquake magnitude, on the other hand, was established. It is assumed that the impact of inertial motions of a deep soil stratum on the inertial motions of upper subsurface soil stratum at instantaneous break of a medium can be neglected. By solving a wave problem for a multilayer near surface stratum, analytical relations were developed for a soil seismogram and accelerogram on the surface depending on the physical–mechanical and dynamic characteristics of the soil at all layers of the stratum; attenuation coefficients of mechanical soil vibrations; the distance to the rupture; and the magnitude of the predicted earthquake. The results obtained enable us to determine the maximum displacement and acceleration values of the soil, taking into account local soil conditions and their variations over time, as well as the values of the predominant vibration periods in the soil. The method was applied for solid and loose soil basements.
Abstract: Problems of the prediction of displacement and acceleration values for strong soil displacements are considered for the case where an earthquake is regarded as an instantaneous mechanical rupture of the Earth’s surface. We have attempted to develop, based on recent concepts of earthquake generation process, simplified theoretical methods for the qu...
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