Typical engineering case of super-deep foundation pit excavated in strata with rock-soil combination in Qingdao, a rocky and mountainous city, is introduced. Considering the special geological conditions and the excav...
详细信息
Typical engineering case of super-deep foundation pit excavated in strata with rock-soil combination in Qingdao, a rocky and mountainous city, is introduced. Considering the special geological conditions and the excavation depth, a supporting system combined with end-suspended piles, anchor cables, steel pipe piles with cutting slope is applied during the course of excavation. Comparisons between the calculated results and the in-situ measured values show that the main deformation of supporting structures concentrates in soil strata in rocky area when the soil strata is relatively thin. With the above-mentioned supporting system, deformations of foundation pits and surrounding strata could be controlled effectively, and meanwhile the engineering cost would be reduced considerably. This will hopefully serve as some beneficial references to similar engineering projects in future.
A new tie-column such as core-column, named as core-tie-column, for the substitution of cast-in-place tie-column was used to improve seismic performance of mansonry structures. Pseudo-static testes of 11 wall specimen...
详细信息
A new tie-column such as core-column, named as core-tie-column, for the substitution of cast-in-place tie-column was used to improve seismic performance of mansonry structures. Pseudo-static testes of 11 wall specimens including 6 walls constrained by core-tie-columns, 2 walls constrained by cast-in-place tie-columns, and 3 walls without constraints were carried out to study the seismic deformation capacity of mansonry walls with core-tie-columns. The skeleton load-displacement curves and the normalized skeleton curves, displacement ductility factors, drift angels of the specimens were analyzed and compared. The effects of the level of vertical compress load, aspect ratio and the wall style on the deformation capacity of the wall with core-tie-columns were distinguished. It is shown that the constraints effects of core-tie-columns on masonry wall are effective and the walls with core-tie-columns have good deformation capacity as those with cast-in-place tie-columns.
There are ways to evaluate the stress of soil nails, but the actual stress is very different from theoretical analysis. In-situ measurements in CNC project in Beijing, mostly adopt the method which lays the reinforcin...
详细信息
There are ways to evaluate the stress of soil nails, but the actual stress is very different from theoretical analysis. In-situ measurements in CNC project in Beijing, mostly adopt the method which lays the reinforcing steel bar-stress measuring apparatus on primary reinforcing steel bar to gain actual pull force when the soil-nailing in working condition. Another method is to contrast the actual pull force with the value calculated by current regulations. The result of the study shows that the stress of soil nails along the length direction appears to be parabola distributing, and the actual pull force in soil nails is no less than 30 kN which is far less than designed stress.
The effect of oxygen content on the morphology of sulfides was investigated by experiment. Experimental results show that the morphology of MnS inclusions changes from Type II to Type I with increasing oxygen content,...
详细信息
The effect of oxygen content on the morphology of sulfides was investigated by experiment. Experimental results show that the morphology of MnS inclusions changes from Type II to Type I with increasing oxygen content, the diameter and area fraction of MnS inclusions increase, but the number and mean aspect ratio of MnS inclusions decrease. The influence mechanism of oxygen content on the morphology of sulfides was studied on the basis of the mathematic model, the Fe-Mn-S ternary system diagram and the Fe-Mn-S-O quaternary system diagram. In the case of the oxygen mass fraction up to 0.022%, the liquid low-melting oxides rich with MnO were found at the early stage of solidification, these oxides made the formation behavior of MnS from eutectic reaction to monotectic reaction, and Type I MnS formed. In the case of the low oxygen content less than about 0.01%, little liquid low-melting oxides rich with MnO were found at the early stage of solidification, most of MnS precipitated in an eutectic mode at final solidification, and Type II MnS formed.
The soft and hard samples were drilled from the different typical mines. The uniaxial and triaxial compressed test of two group of coal samples were carried out with the MTS815 servo-controlled rock mechanics experime...
详细信息
The soft and hard samples were drilled from the different typical mines. The uniaxial and triaxial compressed test of two group of coal samples were carried out with the MTS815 servo-controlled rock mechanics experiment system. Then the strength and deformation characteristics of two group of coal sample were analyzed and the relationship between the lateral deformation and the fracture mechanism was established. The test results show that there are large differences between two group coal samples due to the internal structure and the micro fissures growth degree. The characteristics of lateral strain in hard coal sample is nonlinear obviously and the curve of beyond yield is steep and the value of lateral strain reached the maximum very soon and the stable shear slide model fracture is occurred. While the lateral strain in soft coal sample is increased with small amplitude during the compression progress and the local failure are taken place when the damage evolution arrived in the higher value. And the better results of damage evolution characteristics of coal sample in which the lateral plastic strain is seen as the variable.
Segmentation of mammographic masses is a challenging task since masses on mammograms typically have fuzzy and irregular edges. In the case of tissue adhesion, the region growing algorithm combined with maximum likelih...
详细信息
High energy level dynamic compaction (HELDC) has been especially effective for compaction of coastal macadam fills with large effective depth of improvement. HELDC has been used for increasing in foundation soil stren...
详细信息
High energy level dynamic compaction (HELDC) has been especially effective for compaction of coastal macadam fills with large effective depth of improvement. HELDC has been used for increasing in foundation soil strength and homogeneity. After a brief introduction to the application and detection method of HELDC in the macadam foundation, a large-scaled finite element numerical analysis software, Plaxis, is applied to establish two-dimensional and three-dimensional finite element models for the foundation type. According to field data and empirical in-lab.data, parameters of soil models are determined. The field data and results of FEM analyses are used in this paper to assess the feasibility of HELDC in macadam foundation. Results obtained with different calculation methods are compared with in-situ monitoring data to discuss the feasibility of the two methods and provide some basic references for future designs and calculations.
A discrete mathematical model based on random linear Kalman filtering is introduced to eliminate random disturbance noise in the process of GPS slope deformation monitoring and to improve the validity of monitoring da...
详细信息
A discrete mathematical model based on random linear Kalman filtering is introduced to eliminate random disturbance noise in the process of GPS slope deformation monitoring and to improve the validity of monitoring data. On the base of GPS slope monitoring data in Shuichang Iron Mine, the filtering value of deformation and the velocity of displacement at each point in each stage can be calculated with the mathematical model and the slope deformation at each point in the next stage can be estimated and predicted. It is proved with an example that the deformation obtained by Kalman filtering is more approximate to the real slope deformation.
The indexes system of green degree of biodegradable packaging materials is built and the fuzzy analytical hierarchy process (FAHP) methodology is employed to analyze and assess this system. The qualitative assessment ...
详细信息
The indexes system of green degree of biodegradable packaging materials is built and the fuzzy analytical hierarchy process (FAHP) methodology is employed to analyze and assess this system. The qualitative assessment is gained by the survey and the statistics theory is employed to deal with the qualitative data. The pair-comparison matrix is built and the maximum characteristic root and vector are computed by the sum-product method. Then the relative importance degree of every influence factor is computed and the compositive importance degree of every influence factor is gained. The membership function of every influence factor is established by logical reasoning assignment method, then the membership degree is gained. According to the compositive importance degree and the membership degree of every influence factors, the green degree of biodegradable packaging materials is generally assessed. The green degree of six kinds of biodegradable packaging materials is compared with foamed plastics materials;the result is that the biodegradable packaging materials has wide development prospects.
Critical gap is generally regarded as a constant in existing expressway merging models, but in reality it is a dynamic variable in real vehicle merging. The reason is that there are significant differences and uncerta...
详细信息
ISBN:
(纸本)9780784410394
Critical gap is generally regarded as a constant in existing expressway merging models, but in reality it is a dynamic variable in real vehicle merging. The reason is that there are significant differences and uncertainties among drivers. Based on the cellular automata model, this paper introduces three types of drivers which include aggressive, cautious and general types, and assumes they act heterogeneously with critical gaps. In addition, critical gap function is modified and applied to model the sequence of-decision-making procedures considering the impatience of drivers in the process of waiting for an acceptable gap. According to the established model, the vehicle merging at merge areas can be simulated more accurately. And finally, the velocity-density relationship of the mainline traffic is considered in the condition of forced entry of vehicles from the on-ramp into the mainline. Simulation results show the method based on dynamical critical gap is reasonable and reliable. Copyright ASCE 2009.
暂无评论