岩土工程技术

Reliability Analysis of High Level Backfill Based on Chaotic Optimization

Zhou Chen, Hua Jianxin, Wang Jian

2016, 30(5): 217-222,248. doi: 10.3969/j.issn.1007-2993.2016.05.001

[Abstract](28) [PDF 4026KB](11)

Abstract:
Through full-scale CFG pile field trials,axial force distribution and pile friction and other parameters are measured,the sustained force characteristics and load settlement of CFG pile are obtained,the pile load-sharing case,the pile shaft distribution and lateral friction force are analyzed,the force characteristics of CFG pile is reflected through the field of engineering model.Studies suggest that:Calculation of composite foundation bearing capacity according to the standard formula is not greater than the value of the field load test,pile-soil stress ratio is proportional to the diameter of the root of cushion material and compression modulus,the CFG pile has negative friction resistance,but there is a greater relationship with the construction conditions.

Analysis and Treatment of Soft Soil Foundation Pit Danger in Southern Jiangsu

Zhou Weiming

2016, 30(5): 223-228,234. doi: 10.3969/j.issn.1007-2993.2016.05.002

[Abstract](49) [PDF 12931KB](14)

Abstract:
A typical soft soil foundation pit in Southern Jiangsu,foundation pit is supported by bored pile and cementsoil mixing pile,reinforcement in foundation pit.Engineering construction quality problem and increase of excavation depth result in large deformation of foundation pit.Calculates the internal force and deformation of retaining structure,analyzes the causes of the danger.Reinforcement treatment measures are proposed according to calculation analysis,continued deformation is controlled.

A Foundation Pit Supporting Design Based on Existing Urban Rail Transit Protection

Dong Huichao, Feng Keming

2016, 30(5): 229-234. doi: 10.3969/j.issn.1007-2993.2016.05.003

[Abstract](32) [PDF 2327KB](9)

Abstract:
For the foundation pit near the existing urban rail transit,to ensure the normal operation is the key of the project design.Based on the complex surrounding environment of foundation pit,combined with the engineering geological and hydrogeological conditions,foundation pit excavation depth,the author uses a variety of support types.Through calculation of Lizheng software and finite element analysis,and the engineering analogy,it is proved that the support types can meet the foundation pit excavation and safe use,and ensure the normal operation of urban rail transit.

The Application of the Cement-soil Wall Inserted Door Frame I-steel in an Excavations Engineering

Zhan Jiansong, Zheng Bin, Da Haisheng

2016, 30(5): 235-237,242. doi: 10.3969/j.issn.1007-2993.2016.05.004

[Abstract](33) [PDF 1747KB](9)

Abstract:
Through an engineering example,this paper gives an introduction to the retaining and protection of cementsoil wall inserted door frame I-steel's advantage characteristic,design method and construction technology;according to the analysis of monitoring data comparison after the excavation of foundation pit,that by using the method of deep soft soil foundation pit support can effectively control the displacement,and the effective protection of the nearby buildings;provides reference support method for the similar foundation pit engineering.

Research on Difficulties and Treatment Measures of Phc Pipe Pile Construction in a Blowing Sand Reclamation Plant

Gao Junhui, Wang Wei, Song Pengbo

2016, 30(5): 238-242. doi: 10.3969/j.issn.1007-2993.2016.05.005

[Abstract](38) [PDF 1281KB](7)

Abstract:
PHC pile construction speed is fast,easy to ensure quality,economic,so more and more construction foundation uses prestressed high strength concrete drilled caisson.But penetration of the PHC pile drives the hard formation difficultly,and the total number of hammer is too high to generate pile body fatigue failure,difficult to ensure the quality of pile and construction speed.And if a plant has rich groundwater and a high water table that is higher than that of pile top.in the process of pile sinking with end-open pile shoe,the soil and groundwater will enter inside pipe pile core,and increasing with increment of the depth of the pile.When soil or groundwater is too high in the PHC pile core,in pile-sinking process,water hammer effect is easy to making the pile bady blowout and to causing quality hidden trouble and endangering building security.This paper resolves the problem of such research and gets measures to prevent such issue through research on the actual PHC plie-sinking project in a Blowing sand reclamation plant.

Research on Typical Profiles of Soil Nailing Wall Supporting and Cost Integration

Zhang Ke, Zhang Dongguang, Ma Yongqi

2016, 30(5): 243-248. doi: 10.3969/j.issn.1007-2993.2016.05.006

[Abstract](30) [PDF 1252KB](8)

Abstract:
Since the early 70 s,soil nailing wall has been widely used in foundation excavations project,but the depth,the diversity of soil layer and the difference of soil factors such as restriction,the cost of soil nailing wall control research,there is still no beyond geographical restrictions,still stay in the primary stage.In this paper,combined with the actual case of Wanda,1—2 layers of basement of common soil nail wall support in the form of classification,so as to quickly find supporting cost per linear meter,eventually achieve the goal of soil nail wall supporting cost control.

Design and Practice of Deep Excavation Engineering Adjacent to the Huangpu River in Shanghai

Liao Zhijian

2016, 30(5): 249-253. doi: 10.3969/j.issn.1007-2993.2016.05.007

[Abstract](39) [PDF 3081KB](10)

Abstract:
Shanghai is in soft soil area,which has thick silt soil and high underground water level.But along both sides of the Huangpu River,it has marshland soil in the shallow,which contains silty soil predominantly,and some areas contain much silk clay,the soil fabric is nonuniform and has high compressibility character in this area,different with the conventional regional soil in Shanghai.Taking the deep excavation projects of Shanghai Hejing International Plaza as the background,this paper introduces the selection and analysis ideas of supporting structure in deep excavation engineering which adjacent to the Huangpu River.Some special technologies has adopted in this project,including the construction of large diameter bored castin-place piles and waterproof curtains in marshland soil region,the design of the trestle bridge support system,the method of dewatering and excavation.The monitoring results show that the procedure of construction is safe and the deformation of surrounding facilities is under control.These solutions provide good reference for other similar projects in soft soil regions.

The Stability Research on Dangerous Rock Mass of Xinxiang Town and Its Countermeasures

Zhou Zhou, Luo Xianjun

2016, 30(5): 254-257,265. doi: 10.3969/j.issn.1007-2993.2016.05.008

[Abstract](50) [PDF 1797KB](8)

Abstract:
Dangerous rock mass is a kind of characteristic phenomenon occurred commonly in mountainous areas.At present,studied on deformation development characteristics,failure mechanism and engineering countcmieasure of dangerous rock mass have been the hottest and difficult problem of engineering geology at home and abroad.Based on the engineering example of dangerous rock mass of Xinxiang town,it has been studied systemically on deformation development characteristics,stability numerical methods and countermeasures of dangerous rock mass based on the detailed analysis of the regional geological environment.

Study on the Mechanical Properties of Cement-soil in Erosion Environment

Zhao Guorong, Wang Yan, Li Liangjie

2016, 30(5): 258-261. doi: 10.3969/j.issn.1007-2993.2016.05.009

[Abstract](44) [PDF 609KB](8)

Abstract:
Cement-soil technology has been widely used in engineering because of its lower cost,convenience for construction,and good performance.However,in some engineering,the erosion environment has significant effect on the mechanical performance of cemented-soil.Through the mine waste water,domestic sewage,paper mill effluent,three common erosion environment analysis of compressive strength cement-soil test block in different ages.To reveal the compressive strength of cement-soil test block about erosion environment and age,provides the basis for that the similar environment condition can use cement-soil technology.

Study on Disjoint Floating in Prefabricated Piles Construction and Disposal Measures

Zheng He, Zhang Xu

2016, 30(5): 262-265. doi: 10.3969/j.issn.1007-2993.2016.05.010

[Abstract](47) [PDF 905KB](7)

Abstract:
In this paper,the influence of pile construction on the surrounding environment is introduced,combined with an engineering example,the influence of the section of precast piles with multiple sections on the engineering is analyzed.Due to the limited sampling rate,the static load test may not fully reflect the overall bearing capacity of the pile.In the first part,the low strain method is used to carry out a certain proportion of the sampling to the engineering piles,the high strain and the static load test results which proves the conclusion of the low strain.According to the analysis of the reasons for the Ⅲ piles found in the sampling,it is pointed out that there is a gap between the precast piles in the project.After repressing,the static load method is used to verify the test results,and the results meet the original design requirements.Settlement observation of buildings shows that:the maximum cumulative settlement is 6.54 mm,and the settlement is uniform and stable.

Constraining the In-situ Stress in Anisotropic Rocks from Observations of Drilling-Induced Borehole Failures

Ding Liqin, Wang Zhiqiao, Wang Yu

2016, 30(5): 266-271. doi: 10.3969/j.issn.1007-2993.2016.05.011

[Abstract](68) [PDF 3221KB](11)

Abstract:
Knowledge of the in-situ stress underground is of crucial importance for drilling and reservoir development,the widespread use of wellbore imaging devices made it possible to interpret the local stress state more complete and economical.Breakout azimuths revealed by well logs are widely used to determine principle stress directions in traditional method,however strength anisotropic related to bedding planes may affect both breakout azimuths and widths.which can result in misleading in-situ stress interpretations.Based on weak-plane failure model,we analyzed the relationship between in-situ stress and breakout geometry(azimuth,width and depth).The results show that breakout azimuths are controlled by weak planes' azimuths,while steeply dipping bedding planes widen the breakout and make it deeper.For determined strata property,breakout geometry will change regularly with the increase of the principal stress ratio.A breakout observed in well WFSD-2 help introduce the method for constraining the maximum horizontal principle stress.

2016 Vol. 30, No. 5