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Luo Y.,Chengdu University of Technology | Yu H.,CAS Chengdu Institute of Mountain Hazards and Environment | Wang Y.,Sichuan Institute of Land Planning and Survey | Zheng Z.-J.,The Geological Environment Monitoring Station | Wang X.,China Southwest Geotechnical Investigation & Design Institute Co.
Journal of Donghua University (English Edition) | Year: 2015

Compared with previous studies, the research attempted to establish the appropriate quantitative models to explain the relations between settlement density Di and geographic factors, which could make a scientific guidance to the mountain settlements planning. Five factors, including slope, relief amplitude, distance to river, distance to cultivated land, and distance to road, were identified through principal component analysis (PCA). The inherent relations between five factors and Di (settlement density) were modeled by regression analysis. The results are as follows. (1) The associations among Di and slope, relief amplitude, river, road are better modeled by the exponential decay line; with the buffer distance of slope, relief amplitude, distance to river and distance to road increasing, Di decreases. (2) The associations between Di and cultivated land are better modeled by the quadratic polynomial line; with the buffer distance of cultivated land increasing, Di increases first, and then dramatically decreases. (3) The area within 500 m from the road, within 500 m from the cultivated land, within 1600 m from the river, within the relief amplitude of 30-200 m, and the area within the slope of 0°-10° are the fitting land for settlements, and it is very important to lay the mountain settlements on those optimized regions. Copyright © 2015 Editorial Department of Journal of Donghua University, Shanghai, China. All rights reserved.


Teng Y.,China Academy of Building Research | Wang W.,East China Architectural Design & Research Institute | Kang J.,China Southwest Geotechnical Investigation & Design Institute Co. | Liu J.,Central Research Institute of Building and Construction MCC | Li J.,China Academy of Building Research
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2016

Foundation engineering focuses on determination of foundation type based on properties of subsurface materials, methods of ground improvement and construction, stress and strain analysis of infrastructure, reliability design and environment protection during construction etc. Recently, durability of foundation, transformable function of infrastructure, effective utilization of underground building materials are greatly concerned with the concept of sustainable development. This paper presents relevant advances in foundation engineering within the last five year, including applications of new technologies of in-situ testing, concept of reliability design, anti-corrosion technologies in unfavorable environment, methods tackling special ground. The incorporation of the idea of optimization design is briefly discussed in terms of ground deformation calculation, reliability analysis, setting up a corrosion margin for reinforcement, in order to implement an innovative resource saving design and to provide durable, comfortable living and working conditions. © 2016, Editorial Office of China Civil Engineering Journal. All right reserved.


Xia H.,China University of Mining and Technology | Xia H.,Xuzhou Institute of Technology | Li Y.,China Southwest Geotechnical Investigation & Design Institute Co. | Zhou G.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2015

The physical experiment and numerical simulation of sand-structure interface direct shear were conducted by using DRS-1high normal stress residual shear apparatus and PFC2D (Particle Flow Code in 2 Dimensions) software. The macroscopic representation and inherent mechanism of the mechanical properties of sand-structure interface were obtained. The results show that the strain softening weakens and strain hardening heightens as the roughness increasing under certain normal stress. At same time, the shear displacement corresponding to the peak shear stress reduces gradually. The influence of surface roughness reduces as normal stress increaseing. For the same structure, shear strength at the sand-structure interface meets Mohr-Coulomb criterion. In a certain normal stress conditions, soil particles shear dilation is one of the main reasons which cause the shear strength of the sand-structure interface to change without considering the particle breakage. When the relative roughness R (which is defined as the ratio of peak-valley distance to average particle size, R=H/d50) is smaller, soil particles shear dilation caused by interface constraint and the peak shear stress are all smaller. Both soil particles shear dilation caused by interface constraint and the peak shear stress increase as the relative roughness R increasing. When R increases to a certain degree, soil particles shear dilation caused by interface constraint becomes small. So the peak shear stress reduces too. ©, 2015, China University of Mining and Technology. All right reserved.


Qiu E.-X.,Southwest Jiaotong University | Qiu E.-X.,China Railway Eryuan Engineering Group Co. | Kang J.-W.,China Southwest Geotechnical Investigation & Design Institute Co. | Zheng L.-N.,China Construction Underground Space Co. | And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2015

The holes caused by dissolution in red-bed soft rock are well developed in Chengdu. Submerging test, leaching test and dissolution test are performed with the samples of red-bed soft rock form different depth of Bandao City in Chengdu. Then the influencing on the environmental water and the erosion degree of soluble components in red bed soft rock containing saline deposit under different processes are analyzed after observing the dissolution characters and behaviors of rock sample under different environmental waters. The results show that the content of gypsum in red-bed soft rock rises with the depth increase. The causticity of rock and environmental water is significantly enhanced; the soluble components of red-bed soft rock dissolve and drain gradually under water, so as to turn to pore enlargement, permeability enhancement, strength reduction and lost of integrity; the acid environmental water makes the calcium carbonate cement drains faster and does great damage to the connection of structure, so as to influence the strength of red-bed soft rock obviously. The compressive strength, wave velocity of the rock are tested after submerging test, leaching test and dissolution test. The test results show that the uniaxial compressive strength of the soft rock reduces obviously after corroded by sulfuric acid. The uniaxial compressive strength reduces for 76% from 8.5 MPa to 2 MPa. The wave velocity in the rock also reduces for 40% from 2 204 m/s to 1 355 m/s. Meanwhile, the pH value of the rock reduces from 8.77 to 7.29 and its conductivity increases from 55 μs/cm to 1 100 μs/cm. ©, 2015, Academia Sinica. All right reserved.


Yuan X.-Q.,Beijing University of Technology | Yuan X.-Q.,China Southwest Geotechnical Investigation & Design Institute Co. | Liu H.-Y.,Beijing University of Technology | Liu H.-Y.,Tibet University | Liu J.-P.,Beijing University of Technology
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2016

For the rock masses with non-persistent joints under loading in engineering structures, two conceptions are put forward, which are the loaded microscopic damage and the macroscopic damage with joints. Defining the initial damage state of intact rock as the basic state, considering the existence of macroscopic defect with joints, the damage propagation of microscopic defects, micro cracks and the coupling action of macro and micro defects under loading, the compound damage variable (tensor) is deduced based on the Lemaitre strain equivalence hypothesis. The formula for calculating the macroscopic damage variable (tensor) is given, then the three-dimensional damage constitutive model for the rock masses with non-persistent joints under loading is established based on the coupling of macroscopic and microscopic defects. Finally, the test data are adopted to validate this model, and the effects of macro and micro-defects on the mechanical properties of fractured rock masses under different confining pressures are discussed. The research results show that: (1) The mechanical properties of rock masses under loading in engineering structures are determined by the loaded microscopic damage, macroscopic damage with joints and stress state of rock masses. The mechanical properties of rock masses have obvious brittleness and anisotropies under uniaxial stress, and the anisotropies are largely influenced by the geometric distribution of joints. Under confining pressures, the mechanical properties of rock masses have obvious ductileness, and the anisotropies of rock masses decrease and tend to the isotropies with the confining pressure. (2) The initial axial strain of conventional triaxial compression can not be ignored in higher confining pressure if the compaction of rock masses is considered. © 2016, Chinese Society of Civil Engineering. All right reserved.


Zheng L.-N.,China Construction Underground Space Co. | Zheng L.-N.,China Southwest Geotechnical Investigation & Design Institute Co. | Kang J.-W.,China Southwest Geotechnical Investigation & Design Institute Co. | Xie Q.,Southwest Jiaotong University | And 3 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2014

Research tools for direct shear of geomaterials contact surfaces with strain softening constitutive characteristics is more limited, based on FLAC, strain softening constitutive contact element models is achieved in this paper. Using this element models, the direct shear tests are simulated; the relationships between the shear strength parameters evolution for contact elements and the formal features of shear stress-displacement curves are deeply studied. The progressive failure process of the contact surfaces and the variation characteristics of the internal shear stress are reproduced in the simulation results. The studies have shown that the variation of the friction angle has a major impact on the formal features of shear stress-displacement curves. ©, 2014, Academia Sinica. All right reserved.


Qin H.-L.,China State Construction Engineering Corporation | Zhou T.-H.,Zhengzhou University | Guo Y.-C.,Zhengzhou University | Du C.,China Southwest Geotechnical Investigation & Design Institute Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2014

Basal bearing capacity calculation is one of the important issues for soil nailing wall design. In Chinese excavation engineering, the bearing capacity of soil nailing walls is usually taken into consideration with the basal stability analysis. Soil nailing wall models are established in the Plaxis3D. Finite element method is employed to study the foundation soil's failure mode, the failure loads and the basal stress distribution of the soil nailing wall. The analysis mode in Chinese excavation codes for bearing capacity of soil nailing walls is examined based on the results from the finite element method; and some problems are detected. Referring to the bearing capacity calculation mode for the mechanically stabilized earth walls, and based on the stress distribution under the soil nailing wall, the soil nailing walls are considered as rigid footings with inclined and eccentric loads. The solutions for rigid footings with inclined and eccentric loads proposed by Meyerhof and Vesic are used to calculate the bearing capacity of soil nailing walls. Calculation results show that the solutions by Meyerhof are more consistent with the truth; so that the bearing capacity analysis mode for soil nailing walls is presented. ©, 2014, Academia Sinica. All right reserved.


Fang J.-Y.,Xi'an University of Technology | Dang F.-N.,Xi'an University of Technology | Yan J.-W.,Xi'an University of Technology | Li X.-R.,Emerson eResource Xian Co. | Wang P.,China Southwest Geotechnical Investigation & Design Institute Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2016

In order to study the process of concrete CT test under uniaxial dynamic compression quantitatively, the theory of damage evolution based on fuzzy sets was introduced into the study. Based on λ1-λ2 sets, the CT image was divided into hole or crack zone (P0-λ1), hardened cement paste area (Pλ1-λ2) and aggregate area (Pλ2-1). Furthermore, the porosity, hardened cement paste rate and aggregate rate were defined. Finally, the changing laws of P0-λ1, Pλ1-λ2 and Pλ2-1 in the process of concrete CT test under uniaxial dynamic compression with the variation of loading were studied. The results showed that using this method the quantitative bartition of each component of concrete can be realized; the changing laws of P0-λ1, Pλ1-λ2 and Pλ2-1 in concrete with varying loading can be studied quantitatively; the failure process of concrete can be better described, and the strain localization of a specimen in the failure process can be reflected quantitatively. © 2016, Editorial Office of Journal of Vibration and Shock. All right reserved.

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