Table of Content

20 October 2014, Volume 28 Issue 5 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Reference Manager ProCite BibTeX RefWorks

Toggle Thumbnails

Select

Deep Excavation Supporting Design for Gezhouba Building XU Guoxing1， TAO Zhibin2 2014, 28 (5):  1-3.  Abstract ( 1678 )   Save The Gezhouba Building is located at urban area of Hankou. The excavation depth for the building is between 16.5 and 20.1 meters with a footprint area of approximately 2500 square meters. The shape of the excavation is an irregular rectangular. Due to its depth, this excavation in the urban area with strict environmental constraint belongs to a super deep category. Therefore, it is necessary to select an appropriate excavation supporting method that is most suitable for the subsurface conditions, meeting the safety requirement, having a good constructability and importantly, being cost effective. It is anticipated that the artesian layer will be encountered during the excavation; therefore, the dewatering design is also required for the construction.  Since the soldier pile with rake supporting is a relatively matured technique, the general deep excavation scheme for this project is following: sloping the area to be excavated; castinplace reinforced concrete pile with reinforced concrete raking as supporting system. Jet grout columns as seepage cutoff curtain and as bottom artesian groundwater sealoff with pointwell dewatering system in the middle of the excavated area; soil nailed wall with wire mesh and shotcrete for the slope surface protection. The construction indicates that this supporting scheme is satisfactory. Related Articles | Metrics

Select

Improved Vacuum Preloading Method in Costal Dredged Mucky Soils WU Yuelong, ZHU Fangfang, ZHANG Hong, GONG Lifei, SHENG Dongsheng 2014, 28 (5):  4-8.  Abstract ( 1676 )   Save This paper presents a case history of using an improved vacuum preloading method for the improvement of dredged mucky soils. The construction procedures and the key technical aspects of this improved method are summarized. The monitored data include: settlement, pore water pressure, degree of vacuum, and the vane shear undrained shear strength. The results indicate that this improved method can provide a fast and simple construction soil improvement tool for the coastal dredged mucky soils and the result of this method is satisfactory. Related Articles | Metrics

Select

A Deep Excavation in Guangzhou, Monitoring Results and Analyses ZHAO Xiang, WANG Jieguang, QIN Zhuoping 2014, 28 (5):  9-11.  Abstract ( 1927 )   Save Deep excavation is a typical geotechnical project. Its monitoring work is a comprehensive system and it has the characteristics of time space and environment effects. This paper presents a deep excavation project in Guangzhou. The monitoring dada are analyzed with the site specific geotechnical conditions. The results can be used for the optimization of the excavation design and construction in the future. Related Articles | Metrics

Select

Tangjiawan Eastern Slope Seepage and Stability Analyses and Mitigation Measures HE Jinxun, WANG Jieguang， HUANG Chuangjie 2014, 28 (5):  12-15.  Abstract ( 1797 )   Save The seepage field change and slope instability induced by the fluctuation of the reservoir pool levels are presented in this paper. The engineering geologic conditions of Tangjiawan Eastern Slope are discussed based on the geotechnical engineering investigation data. The seepage fields under the pool level fluctuations are numerically simulated by using GeoSlope software. The slope stability of the Eastern Slope under the pool level fluctuation is analyzed by considering the matric suction in the soil mass and its effect on the residual thrust force in the analysis. The mitigation measures are proposed accordingly. The construction monitoring data indicate that this proposed mitigation method is effectively controlled the deformation of the reservoir slope. Related Articles | Metrics

Select

Stability Analysis and Mitigation Solutions of a Landslide at Shiqian Springs Road in Guizhou MA Ning， ZHAO Yejiang 2014, 28 (5):  16-19.  Abstract ( 1615 )   Save The case history of a landslide at Shiqian Springs Road in Guizhou is presented in this paper. The site environmental geology conditions, geotechnical information of the subsurface conditions are analyzed based on the site specific investigation dada. The stability analyses along different soil strata are performed by using block failure method. The factor of safety of the site is obtained as a result of the analysis and the mitigation measures are proposed. The investigation results indicate: The slope is located on a daylight site. During the long construction period and under prolonged heavy precipitation, the unit weight of the surficial soil is increased and the shear strength of the sliding surface is also reduced, therefore, the geological hazards, such as landslide, might be triggered. Related Articles | Metrics

Select

A Memoir of the Risk Mitigation and Engineering Improvement for the Shimen Reservoir JIANG Fanghao 2014, 28 (5):  20-23.  Abstract ( 1687 )   Save This memoir documented potential engineering risks of the Shimen Reservoir. The typical issues currently identified are: overall stability of the dam and its base, seepage and leakage, spillway congestion, various defects of the main channel, cracking and carbonizing of concrete from accessary structures of the reservoir. Additionally, the standard used in the original dam design may be inadequate to current needs. The lack of sufficient safety monitoring during the service life may also be an adverse factor. Upon recognizing these engineering problems, a number of risk mitigation measures were implemented, including slope and base stabilization for the dam, cutoff wall strengthening, dredging, spillway improvement, widening and reinforcing of the main channel, concrete strengthening, repairing existing monitoring facilities and adding new ones, etc. Results illustrated that these engineering treatments have effectively controlled and minimized risk concerns. Related Articles | Metrics

Select

Seismic Design and Anaysis of A Triangular FrameRC Core Wall Structure SHEN Jiepan1, LIN Chen2, WU Shuai1 2014, 28 (5):  24-27.  Abstract ( 1708 )   Save Based on a triangular frameRC core wall structure, the selection, arrangement and seismic design of structure were discussed starting from the seismic conceptual design. The seismic performance of the structure was evaluated under frequent earthquakes and rare earthquakes. The critical element of the structure was calculated under earthquake resistance. The analytical results showed that the structure had well seismic performance; the arrangement of structure was reasonable and the seismic tectonic measures were put forward on this basis. Related Articles | Metrics

Select

Preservation Measures for Geological Relics--A Preliminary Evaluation Based on Engineering Practices on Jimo Mashan Stone Forest WANG Rengang1, YUAN Xilong1, QIU Dalu2， LIU Zongyan2 2014, 28 (5):  28-30.  Abstract ( 1533 )   Save The Mashan region of the City of Jimo contains a variety of geological relics, such as columnar jointed rock masses, petrified wood fossils, and contactolites, etc. There are pressing needs for the preservation of these unique geological features. In order to achieve a desirable overall result, the effectiveness of each individual method is worth investigating. This paper presented a number of proposed preservation measures for Mashan stone forest and petrified wood fossils, including removal of unstable rocks, rock slope resurface, winderosion treatment for rocks and fossiles, site drainage improvement, construction of inspection channels, installation of security fences and live monitoring network systems, etc. Additionally, exhibition halls for otherwise abandoned petrified wood were invested. The actual implementation of each of these measures verified its engineering feasibility and effectiveness. Related Articles | Metrics

Select

Excavation Monitoring for Proposed Lift Pump Stations Around the Terminal 3 of the Shen Zhen New Airport GUO Yong1, CAI Hanli2, HU Shenggang2， TAN Fengyi2 2014, 28 (5):  31-32.  Abstract ( 1583 )   Save Contract No.2 of the Shen Zhen Airport Transport Services project involved a total of three (3) lift pump stations being proposed at the east, west and south side of the "Terminal 3", respectively. The construction required 8-10 meter deep excavations. Due to the large presence of the very soft silt and clay marine deposits, the excavations were sustained utilizing a piling system consisting of drilled shafts with monotubed churning piles in between. Additionally, a layer of steel pipe internal brace with C20 shotcrete was used to further maintain the stability. These multiple measures added challenges to the construction. For safety concerns, a monitoring program was conducted during each stage of the excavation and shoring installation, as well as during each individual construction period of the overall project. The monitoring efforts were focused on the deformation of the shoring system. Results based on the monitoring data showed that such a comprehensive supporting system may be suitable for deep excavations through marine deposits that are typically featured with very soft silt and clays. Related Articles | Metrics

Select

Stucture Desigh of Double Shield TBM Tunnel in Complicated Geological Condition and Its Application in DABAN Diversion Tunnel XI Zhuhui1, XIN Fengmao2, ZHANG Lei1， ZHANG Yuelin2 2014, 28 (5):  33-35.  Abstract ( 1544 )   Save The Daban diversion tunnel has complex geological conditions. The paper discusses the detail structure design of the lining segment socket joint, seepage prevention and capillary drainage tubes in the tunnel. The solutions for the tunnel in the complex geologic conditions are also proposed. Related Articles | Metrics

Select

Application of a Composite and High Performance Liquid Concrete Accelerator in Baoyi Highway Tunnel Construction DU Wei1, HU Junchao1, LIU Jianguo1, FANG Lijun2 2014, 28 (5):  36-38.  Abstract ( 1495 )   Save The shotcrete supporting technology is essential part of the tunnel construction. Among other potential factors, the concrete accelerator has an important impact on the quality of the shotcrete. A new composite and high performance liquid concrete accelerator agent is used in the tunnel project in Baoyi highway tunnel construction. It is consists of several components and has the characteristics of small application amount, wide applications, and small strength loss. This agent is approximately 1.5% to 3% of the cement weight and the initial setting time is approximately one minute and the final setting time is within four minutes. The strength loss at the later stage is within 10%. The application results indicate that this liquid agent has characteristics of small rebound and waste slurry. Related Articles | Metrics

Select

Compaction Effects of PHC Pipe Piles in Alluvial Plains of Yellow River JIANG Hao1, LV Yinghui2 2014, 28 (5):  39-41.  Abstract ( 1379 )   Save The soil properties are affected by the compaction effect of Prestressed High Concrete (PHC) pipe pile installations. The case history of a PHC pipe pile installations for a power plant project in the alluvial plains of Yellow River is presented in this paper. The compaction effect of the PHC pipe piles are studied by comparing both the insitu and laboratory tests before and after the pile installations. The results indicate that the compaction effect increase with the reduction of pile spacing; the compaction effect reduces with the increase of the clay content in soils. The compaction effect is more obvious in silty and sandy soils than that of in clayey soils. If applied appropriately, the PHC pipe pile can be used to increase the shear strength of the surrounding soils and eliminate the liquefaction potential. The liquefaction degree can be reduced but this reduction is getting less effective with the increase of pile spacing. Related Articles | Metrics

Select

Application of Heavy Vibratory Rollers in Xi'an Central Container Station YU Lifen 2014, 28 (5):  42-43.  Abstract ( 1634 )   Save This paper presents a case history of using a heavy vibratory to eliminate the potential wetting settlement of loess soil deposits in the Xi'an Central Container Station Project. The principles of the heavy vibratory rolling technique are briefly introduced. After the rolling compaction, the degree of compaction bearing capacity and the modulus of compression have increased and the wetting settlement of the loess soils can also be effectively eliminated. Related Articles | Metrics

Select

Quality Control on the Deep Seepage Cutoff Walls for Strengthened Coastal Soils LIU Yingjun 2014, 28 (5):  44-46.  Abstract ( 1677 )   Save This paper presents the deep excavation results for the Line No. 5 of Shenzhen Metro. The failure of the seepage cutoff wall is systematically analyzed through different aspects: engineering geology, construction procedures, equipment and construction quality control. The effects of different factors on the seepage cutoff wall are discussed and the mitigation measure is also proposed. Related Articles | Metrics

Select

Analysis of the Stability of the Filled Embankment Slopes under Reservoir Pool Level Fluctuations ZHAN Huiming，WANG Yaohui, ZHOU Zenghui 2014, 28 (5):  47-49.  Abstract ( 1670 )   Save Reservoir pool level fluctuation is considered as one of important factors that induced the reservoir landslides.  The impact of the pool level fluctuation of Bokou Reservoir on the Aoyugou filled embankment slopes is analyzed be the combinations of seepage field finite element method (FEM) and limit equilibrium method. The results indicate: the safety factors on the embankment slopes are reduced initially and increased later under the pool level fluctuations. The large deformation of the embankment slopes occurred during the initial stage of pooling and discharging periods. A stable status can be found during the later stages of both operations of pooling and discharging. Related Articles | Metrics

Select

SolidLiquid Coupled Analysis of River Crossing Pipe Lines 2014, 28 (5):  50-52.  Abstract ( 1756 )   Save The seepage problem is a prevailing issue in the excavations under saturated conditions. For the geotechnical projects, it is very important and necessary to study the seepage field properties and the stress strain status under the seepage actions.  This paper presents the numerical simulation results of a pipe line project cross the Sheshui River by using FLAC3D software. The results indicate: under the seepage action, the deformation and the stress have a significant increase in both the surround rock mass and the jacked pipe line. Therefore, the seepage action should be considered for the excavation support design and construction. Related Articles | Metrics

Select

Finite Element Analysis of Impact of Cushion on the Skin Fiction in Columns of the Composite Grounds TANG Kai，ZHANG Jianlong, QU Jianglong 2014, 28 (5):  53-55.  Abstract ( 1684 )   Save The effect of thickness and the deformation modulus on both the positive and the negative skin frictions and the neutral position of the single column in a composite ground under the ground surcharge have been analyzed by ABAQUS finite element software. The results indicate that, when the loads and the cushion modulus are constant, the increase of the cushion thickness will help the development of the positive skin friction and the neutral point will be at a higher position; when the thickness of the cushion is less than 0.5 meters, the increase of the cushion modulus will increase the positive skin friction and the neutral point location will also be higher; but the raise of the neutral point is not as obvious as when the cushion thickness is great than 0.5 meters. The numerical analysis on the impact of cushion thickness and the modulus on the single column in a composite ground will help the understanding of the load transfer mechanism. Related Articles | Metrics

Select

ColumnSoil Stress Ratio Analyses in a ColumnReinforcing Netting System YIN Yuxia1， CHU Yunsong2 2014, 28 (5):  56-59.  Abstract ( 1681 )   Save The columnreinforcing netting composite ground is a soil improvement system consisting of column, reinforcing netting, and surrounding soils. This system has different functional elements, such as, column, cushion, drainage layer, reinforcement and protection. This paper presents and theoretical analysis results as well as the tested columnsoil stress ratio data in the actual projects. The change of stress ratio between the column and the soil with the column spacing, reinforcement netting materials, length of the columns, loading magnitude, column materials and soil properties are carefully studied. Related Articles | Metrics

Select

Model Tests and Numerical Analysis of Deep Excavations Considering Space Dimensions WANG Ting1, TANG Bin1, ZENG Zhe2 2014, 28 (5):  60-62.  Abstract ( 1781 )   Save The influence of the space dimensions on the deep excavation is investigated throughout the model tests as well as the numerical simulations by using ABAQUS software. The results indicate that the optimized deep excavation dimensions in a model are: the ratio of length in the active zone B1 over the cantilever length is 1.50. The ratio of length in the passive zone B2 over the embedment depth of the cantilever portionL2 is 3.0.   Related Articles | Metrics

Select

Discussions of Soil Nailing Wall Design and Construction in Weathered Rock Zones LIU Qi1, DU Pengxiang2 2014, 28 (5):  63-65.  Abstract ( 1826 )   Save This paper presents the results of determination of the internal friction angle of the rock mass based on the project experience and the design code requirements. The cohesion of the rock mass is back analyzed by using the MohrCoulomb criterion under uniaxial stress. The design parameters of the rock mass are used in the soil nailing wall supporting design. The hollow soil nails' penetration depth is correlated with the blow counts of the Standard Penetration Test. This empirical relationship provides a reference value for the design of the required length for the hollow soil nails. The paper also presents the engineering considerations for the soil nail applications in the cold regions that are affected by the freeze expansions. Related Articles | Metrics

Select

Statistical Study of Physical and Mechanical Indexes of the Tailing Silt YU Chenxiang, CHENG Jiangtao, CAI Qing 2014, 28 (5):  66-69.  Abstract ( 1778 )   Save The evaluation the correlations among the physical and mechanical properties of the finegrained tailing soil is of great significance on the reliability research of physical and mechanical parameters as well as the saving soil test cost. This paper presents the results of the regression analysis on the physical properties by using both mathematical statistics and linear regression analysis methods. The empirical relationships between mechanical properties and physical properties are established. The statistical analysis results indicate, there is no significant variance in the physical and mechanical properties of tailing silt and a strong correlation can be found. For the design purposes, the average values of the tailing silt soil physical and mechanical index values can be used without considering the variability. Related Articles | Metrics

Select

Discussions of Soil Mixing Wall Procedures WU Fagen1， LI Tingjie2 2014, 28 (5):  70-73.  Abstract ( 1443 )   Save This paper presents the uplift resistance mechanism and its estimation of the rolled steel in the Soil Mixing Wall (SMW). The upliftdeformation estimation methods are compared by different analytical models and it is concluded that, in the uplift estimation, the contribution of the SMW rigidity needs to be considered. The paper also presents the reference rigidity values of the SMW. Related Articles | Metrics

Select

Rock Mass Characteristics of Porphyry CopperMolybdenum Mine in Ekendrest, Qinghai ZHAN Shouzhi1, CHEN Haifu2, LI Liansong1 2014, 28 (5):  74-78.  Abstract ( 2000 )   Save The Ekendrest CopperMolybdenum Mine is located in a complex broken geologic zone at the east side of South Qunlun Mountains. The mine bedrock outcrop belongs to Triassic Flood Chuan Group. The orientation of the rapture is predominantly in the NorthWest direction, and then NorthEast and close to SouthNorth directions. Among these rapture directions, the raptures in the NorthWest direction have a large quantity and a long development period. They formed broken zones with different sizes near the ground surface and they directly influenced the space distribution of bedrock strata, ignite rock mass and mine porphyry rock mass. This paper present the geological properties and geochemical properties of the porphyry coppermolybdenum rock mass of Ekendrest Mine.  The results indicate that, the minestrip in the rock mass and its surroundings have similar geological characterizations, that is, both the chalcopyrite and molydbenite are deposited in the fissures of the rock mas in small strips and usually combined with quartzite crystals. The mine strips have the properties of coppermolybdenum in porphyry rock mass. The porphyry rock mass is the source of the mine. The acidic porphyry granite rock mass has a beaded output with a higher than 72% of SiO2 contents. The total content of rare earth is relatively low but with a higher concentration of light rare earth elements and strong fractionation. The heavy rare earth elements, however, is relatively absent with a weak fractionation. An obvious "V" shape distribution of the Eu element can be found in the mine, which is the reflection of the local melting of the shellsource materials. The rare earth elements, Ba, Rb, Th, and K have an obvious concentration. The next concentration elements are: La, Ce, Zr and Hf. The other elements are relatively absent. A comprehensive study on geological characteristics of the mining producing using the the existing data of the Ekendrest Mine, new mine locating method can be developed and therefore, leads to a better understanding and mine locating of the entire area. Related Articles | Metrics

Select

Influence of Tunnel Excavation on the Slope Stability LIU Zhiwei 2014, 28 (5):  79-82.  Abstract ( 1757 )   Save The tunnel within a slope is modeled by twodimensional finite element method.  The impact of different excavation locations on the slope stability was compared on the analytical model. The results indicate that, the stability of the slope has very minor impact when the excavation is performed at the top of the slope, but this has little practical applications. When the tunnel is excavated to the middle of the slope, an obvious deformation on the slope can be found. A significant disturbance on the slope soils even failures can be resulted when the excavation is approaching to the bottom of the slope. An optimized tunnel excavation zone can be determined throughout the numerical analysis and the result can provide guidance to the tunnel design and constructions. Related Articles | Metrics

Select

Considerations of the Wave Velocity in the Integrity Index Calculations in Rock Samples TANG Shenggui, LIU Faxiang, TANG Guanghui 2014, 28 (5):  83-86.  Abstract ( 2125 )   Save After a discussion on the measurement of the compressive wave velocity in the formula of the rock mass integrity index as well as the representative wave velocity values, it is concluded that the rock mass integrity index estimation should be focused on the same type of rock mass with similar properties. The representative wave velocity in the rock mass in the engineering practice should be obtained by the statistical methods. It is unreasonable to use the maximum compressive wave velocity measured as the wave velocity in the intact and fresh rock sample. Once the mean value, maximum average value, minimum average value, median value and the standard deviation value are determined, the reliable compressive wave velocity value should be analyzed by its frequency distribution. Related Articles | Metrics

Select

Application of Geophysics Methods in the Geotechnical Investigation of Thick Sand and Boulder Soils GUO Hongmei 2014, 28 (5):  87-90.  Abstract ( 1461 )   Save This paper presents the investigation results of thick sand and boulder soils for a high-rise building site. Geophysical testing methods, such as, wave velocity, pulsation, resistivity, transient electromagnetic and seismic wave, are used as complimentary testing methods to the conventional geotechnical investigation methods. These methods provide useful information for the site characterizations. Related Articles | Metrics

Select

Application of Dynamic Compaction Method for Large Areas of Deep Clay Backfills GONG Lifei1,2, JIANG Yunjie3, CHEN Dongdong2， ZHOU Dan2 2014, 28 (5):  91-95.  Abstract ( 1613 )   Save This project site was backfilled with silty clayey and clayey soils with weak expansive potentials. The maximum backfill depth is 8 meters. The dynamic compaction method was utilized to improve the site.  Different dynamic compaction trial parameters and monitoring programs are used in different areas with different backfill depths. The results indicate that, the compaction energy of 3,000 kN·m and a spacing of 6 meters has a better results than those area compacted by the compaction energy of 2,000 kN·m and a spacing of 5 meters.  The depth of backfills should be considered first when the compaction parameters are to be selected. The results can be optimized by adjusting the compaction spacing, number of drops at each compaction point in the trial compactions. Related Articles | Metrics

Select

Analysis of Pressuremeter Curves and Their Characteristics with Depth CHEN Mingxing， SHEN Shaohua 2014, 28 (5):  96-98.  Abstract ( 1900 )   Save The insitu Pressuremeter test results from boreholes No. 1 though No. 6 in Songta Hydropower Plant project indicate that the characteristics of the deformation curve in the compression phase is critical to a successful test and the reliability of the test. The linear deformation and the failure phases are closely related to the engineering properties of the soil strata tested. The Pressuremeter test results from borehole No. 7 through No. 9 indicate that the variations of the curves with the depth in the same soil stratum are similar with a different radius. Summarizing the test results can help the proper characterization of the soil properties at different depths.  Related Articles | Metrics

Select

Excavation Blasting Vibration Monitoring and Analysis in the Tianjingshan Tunnel ZHAO Dongqi， ZHAO Canyuan 2014, 28 (5):  99-101.  Abstract ( 1667 )   Save The excavation blasting vibration monitoring of Tianjingshan tunnel results are presented in this paper. The measured peak particle velocities (PPV) in the adjacent tunnels are 0.11 cm/s and 0.10 cm/s, respectively. And the maximum vibration direction is in the radius direction that is perpendicular to the tunnel wall. The results indicate that the blasting excavation method used in the Tianjingshan Tunnel has a minor impact on the adjacent tunnels. The stability and safety of the effect tunnels can be warranted. It is also concluded that the stress wave induced by the blasting is significantly reduced in the broken rock mass and the code requirements seem to be conservative. In the construction, the PPV can be adjusted accordingly if a comprehensive monitoring program is implemented. Related Articles | Metrics

Select

Geological Prediction of Shallow Buried Tunnel Excavations and Monitoring ZHU Zhongquan1,2 2014, 28 (5):  102-105.  Abstract ( 1476 )   Save The advanced geological forecast and monitoring measurements of tunnels are indispensable parts of construction for the New Austrian Tunneling Method. These monitoring and measurements can accurately forecast the quality of the rock mass within a certain distance from the tunnel excavation face and provide realtime stability information of the tunnel wall and supporting structures. They can also provide the large deformation warning in the tunnel excavation and ensure the proper excavation procedure can be implemented. The excavation of the shallow buried Shanxi Tunnel is presented in this paper. Both the predicted and monitoring data during the tunnel excavation are analyzed. It is concluded that the deformation rate in the rock mass could be affected by the construction methods. The stresses within the steel supporting structures as well as within the rock mass are correlated with the deformation rate at the excavated surface in the shallow buried tunnel. Related Articles | Metrics

Select

Understanding and Mitigation of the Channel Slope Failures Due to the Presence of Expansive Soils BAO Chenggang 2014, 28 (5):  106-114.  Abstract ( 2021 )   Save The detrimental effect of expansive soils to slope stability is commonly observed and remains a great challenge in geotechnical engineering. Due to the poor understanding of the failure mechanism, the engineering solution could be sometimes less effective. This paper summarized two (2) typical slope failure modes upon structural evaluations of expansive soil strata based on two full scale insitu tests combining with other reported failure examples in real engineering practices. The two observed failure types are: surficial failure due to the sliding of the expansive soils; and, mid fissural failure circle. This study further investigated the mechanisms and factors controlling the slope failure and provided recommendations for potential engineering solutions. These findings would provide helpful information to understand slope failures due to the presence of expansive soils. Related Articles | Metrics