岩土工程技术

Study on Seepage Volume Calculation of Suspended Curtain and Effect of Depth into Soil

Zhang Qinxi, Chao Zhe, Zhang Xuedong

2018, 32(3): 109-114. doi: 10.3969/j.issn.1007-2993.2018.03.001

[Abstract](62) [PDF 1892KB](16)

Abstract:
In order to confirm relationship between flow rate of foundation pit and suspended curtain depth into stratum and relationship between maximum water level reduction of outside the foundation pit, so then finding the optimum value of suspended curtain depth into stratum, according to Darcy’s law and large-well-method, formula was derived. By comparative analysis of example of derived formula and Davidenkoff's way,the similarities and differences of the results was discovered. Groundwater seepage in foundation pit was simulated by laboratory model experiment and Midas/GTS/NX, verifying derived formula and coming to conclusion, which maximum water level reduction of outside the foundation pit was discussed slightly with increasing of suspended curtain depth into stratum and flow rate of foundation pit was reduced.

Study on Design and Application of Deep Mixing Method with Double Wheel Trench Cutter

Ji Xiaopeng, Zeng Jianhua, Che Dong

2018, 32(3): 115-119,124. doi: 10.3969/j.issn.1007-2993.2018.03.002

[Abstract](106) [PDF 2717KB](18)

Abstract:
This article briefly introduces the feature,design theory,design content,and construction process of the deep mixing method with double wheel trench cutter(CSM). In combination with practices and application, the article also analyses the features and advantages of CSM technology,thereby providing robust basis for promotion and application of this technology in China.

Quality Analysis of Virtual Reference Station Observation Data Based on Beijing CORS System

Wang Shengguo, Zhu Zhaorong, Zhang Xiyue

2018, 32(3): 120-124. doi: 10.3969/j.issn.1007-2993.2018.03.003

[Abstract](53) [PDF 853KB](11)

Abstract:
Aiming at the situation that one may not obtain the fixed network RTK solution in some specific VRS environment,this paper presents a control point calculating method based on the virtual station observation data. The virtual reference station observation data is generated by Trimble Pivot software, then the coordinate of observation point can be obtained within TBC software by baseline processing and adjusting together. The results show that the quality of the virtual reference station observation data is equivalent to the real station observation data and is reliable. In addition, the three-dimensional precision of the control points obtained by using the virtual site network solution is better than 5 cm.

Simulation Study of Soil Triaxial Compression Based on Drucker-Prager Yield Criterion

Li Zhongxiang, Guo Lin, Cai Fei

2018, 32(3): 125-126,145. doi: 10.3969/j.issn.1007-2993.2018.03.004

[Abstract](57) [PDF 643KB](9)

Abstract:
The Drucker-Prager yield criterion was used as plastic condition of soil,using finite element analysis software to soil triaxial compression numerical simulation experiment according to project example, and obtaining the following conclusion: it can truly reflect the elastic-plastic deformation in geotechnical engineering, it can be widely used in elastic-plastic deformation problems in geotechnical engineering.

Monitoring and Analysis of Landslide in K13-K14 Section of the South Loop,Fuxin City

Zhang Muchen, Wang Changming, Zhang Lixin

2018, 32(3): 127-131. doi: 10.3969/j.issn.1007-2993.2018.03.005

[Abstract](41) [PDF 3897KB](10)

Abstract:
With coal mining,a large number of abandoned coal gangue be piled up to form high and steep slope. The stability of high slope is poor. Landslide could be caused by one or several of unstable factors. In this paper, the surface displacement monitoring technique of landslide is used to monitor the subgrade landslide of K13—K14 section of fuxin south ring road.And the trend of further short-term surface deformation of the landslide is studied. Studies have shown thatthe surface displacement of landslide is in the direction of 175°. At present, the slope is in uniform deformation. During the monitoring period, the surface displacement has changed greatly and the trend has been developed. Measure should be taken in a timely manner.

Discussion on Earth Pressure of Retaining Wall

Gao Qingsong

2018, 32(3): 132-134. doi: 10.3969/j.issn.1007-2993.2018.03.006

[Abstract](48) [PDF 384KB](19)

Abstract:
In some special parameters, the result of active earth pressure calculation according code for design of building foundation is abnormal. The article discuss the reason and suggest modified formula.

Geotechnical Engineering Investigation Analysis of Some Super High-rise Building

Guo Hongmei

2018, 32(3): 135-139,163. doi: 10.3969/j.issn.1007-2993.2018.03.007

[Abstract](61) [PDF 5390KB](17)

Abstract:
The exploration and in-situ measurement methods of sand and pebble layer of some super high-rise building of 200 m high on sand and pebble subgrade in Beijing in the paper, it analyses the important and difficult points of the project. Analyzing key technical question of the project, adopting comprehensive investigation methods such as digging, resistivity test,ground pulsation test,in-situ direct shear test, shallow seismic prospecting, TEM, numerical simulation and cooperative settlement computing methods, putting forward corresponding technical countermeasures being directed at key technical question of the project,adopting design method of variable stiffness leveling foundation, attempting to adopt natural foundation scheme. It provides reference for similar projects.

Construction Technology of Fully Weathered Granite Water Rich Stratum in Tunnel

Ma Jiapei

2018, 32(3): 140-145. doi: 10.3969/j.issn.1007-2993.2018.03.008

[Abstract](61) [PDF 1735KB](8)

Abstract:
Body section at a length of 340 m of left line and 290 m of right line of Xiaotiandu Tunnel is water-rich fully and strongly weathered granite stratum, which has a large deformation of excavation. Taking the above area as the object of study,exploring the construction techniques for water-rich fully and strongly weathered granite section of Xiaotiandu Tunnel,and controlling the deformation of surrounding rock. The results show that: Adopting the annular excavation of three steps reserved core soil together with advance support can control the deformation of surrounding rock effectively and reduce tunnel crown settlement;Water-rich fully and strongly weathered granite can significantly reduce its strength meeting with water, adopting the water diversion and drainage in tunnel and well-points dewatering outside of tunnel can reduce the water content of surrounding rock effectively,and then reduce the risk of water collapse effectively,guaranteeing the safety and schedule of tunnel construction. The obtained results can provide reference for the construction of large cross section tunnel under similar geological conditions.

Research on Wave Compensation Technique for Standard Penetration Test at Sea

Hu Jianping, Wang Nianxi

2018, 32(3): 146-150. doi: 10.3969/j.issn.1007-2993.2018.03.009

[Abstract](73) [PDF 850KB](7)

Abstract:
At present,there are clear and detailed terms of use for the standard penetration tests of geotechnical investechnical in China and abroad. In the sea investechnical,the drilling rig fixed on the shipboard platform is affected by the fluctuation of the wave and the process of falling hammer, the investigation equipment cannot control the distance of the 76 cm height of the falling hammer, so that the standard penetration is distorted. This paper aims at the design of the control scheme of the marine standard penetration drop hammer, the research of compensation module and computer control, which aims to extend the land SPT to sea and meet the requirements of ocean engineering,is of reference value to improve the standard of penetration in-situ test of marine engineering standards and to accelerate the development of marine reconnaissance equipment technology.

Mechanism of Bearing Capacity of Tight Confined Pile

Zhang Yongjiu, Li Guangxin

2018, 32(3): 151-154. doi: 10.3969/j.issn.1007-2993.2018.03.010

[Abstract](42) [PDF 815KB](7)

Abstract:
The construction equipment and technology of tight confined pile are introduced. It is pointed that the increase in bearing capacity of the pile results from the densification of the soil under point of pile and around pile shaft. The results of load test of pile in two sites have shown that the tight confined pile has great potential in engineering application.

Application of Geophysical Prospecting Method in Site Surveying of Subsidence

Liu Yongsheng, Liu Renyi, Ma Ruiguang

2018, 32(3): 155-158. doi: 10.3969/j.issn.1007-2993.2018.03.011

[Abstract](89) [PDF 2959KB](17)

Abstract:
Ground subsidence is a geological disaster with sudden and disastrous characteristics which strongly affects the life and property safety of all kinds of facilities and residents within the region. As a fast and efficient method of exploration, geophysical prospecting technology can play an important role in ground subsidence exploration. This thesis discusses the effectiveness of the combination of transient electromagnetic method, high-density electric method and surface wave method through the case study of ground subsidence exploration.

Based on Dynamic Test of Foundation Study on Improvement and Application of Electromagnetic Vibrator

Zhang Kaiwei, Li Zhiyong, Ma Qingzhou

2018, 32(3): 159-163. doi: 10.3969/j.issn.1007-2993.2018.03.012

[Abstract](40) [PDF 946KB](11)

Abstract:
Based on the problem of insufficient excitation force caused by the excitation of the exciter in the forced vibration excitation test of the traditional ground, a method is proposed to increase the exciting disturbing force by using the parallel double multiplying force electromagnetic excited vibration. To this end, we first analyzed the shortcomings of the common mechanical vibration exciter, puts forward the design and improvement methods of parallel double double force electromagnetic vibration exciter, and then combined with the incentive effect of the difference between the actual project test data comparison,find out the different frequency of driving function between the current and the amplitude frequency response, finally through different types of foundation the actual test results show that the parallel double double force electromagnetic vibrator can not only satisfy the curve of amplitude and frequency characteristics of natural foundation soil with low frequency requirements can meet the requirements of the rock foundation and pile foundation block based high frequency amplitude frequency characteristic curve,the test of frequency response curve the true frequency response in a wide range of threshold, but also improve the mechanical vibration force and low bandwidth limit is not suitable for rock foundation and the pile body block vibration test based problem that parallel double double force electromagnetic vibrator can be used force of foundation soil forced vibration test, further verify the forced vibration tests parallel double double force generated electromagnetic vibration exciter for double force pile block foundation is feasible.

2018 Vol. 32, No. 3