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In order to explore the relationship between the critical bearing capacity and settlementof closed pile tip pierced into the soil, based on the Boussinesq solution and the Kelvin solution, the analytical solution between the critical bearing capacity and the critical settlementof the closed pile tipis derived by combining the stress distribution function.The analytical solution of critical bearing capacity and settlementof pile tip is verified by field test of static pressure pile penetrating into layered soil with a full-section pressure sensor installed at pile tip. The results show that during the penetration process, the bearing capacity increase stage of the pile tip is divided into linear steepening section and nonlinear slow increasing section. The soil in the linear steep increase section behaves as an elastic state. The bearing capacity of the pile tip before the punctured soil layer is linear with the settlement, and the final value of the linear steep increase section is the elastic limit value and the critical bearing capacity of the piercing pile tip. When the residual pile tip force is not considered, the critical settlement of the pile tip is between 0.095-0.119d; when considering the residual pile tip force, the critical settlement is between 0.091-0.105d.In particular, when the Poisson's ratio is 0.5, the analytical solution of the semi-infinite space is equivalent to the analytical solution of the infinite space.

At present, the constructionindustry is in urgent need of a big transformation from the traditional extensive development model to achieve transformation and upgrading. The cooperative application mode of lean construction and BIM is the important driving method of this change. It effectively solved the information technology problems in the process of lean construction implementation. Meanwhile, the lean construction system also provides a better application environment for BIM and fully realizes the technical value. From the perspective of multiple applications, this paper introduces in detail how BIM uses its technical advantages to enhance the application value of lean construction in the construction industry.

In the construction process of high-rise building structure, the formwork temporary supports and the concrete structure are considered as a whole. Quantifying the load under the template supports can provide a better reference for the design of the template supports. In order to study the load transfer law between formwork support scaffolds and multi-storey structure, through the installation of sensors at the bottom of formwork supports and the floor slab, the load transfer law of the 3 adjacent formwork supports were monitored for a long time during the construction of high-rise buildings via the high-frequency wireless transmission systems. The main conclusions are as follows: (1) The monitoring data shows that the most unfavourable load occurs when concrete is poured into the upper story, about 1.9 times the axial force generated when concrete is poured into the test floor. (2) The monitoring data has a similar shape which is summed up as an ideal curve of change, 3 times of peak value, 3 times of decline and 1 time of sudden drop. (3)The transfer ratio of load accounts for about 57% ~ 69% of a total load of fresh concrete. (4) Considering the fluid-plastic state of concrete, a correction factor of 1.22 for vertical pole axial force is proposed, and the deviation between the modified simulated value and the measured value is less than 3%.

When the open-ended pile penetrates the soil layer, the resistance generated by the soil plug cannot be ignored. A pile with a full-size pressure sensor installed at pile tip can detect resistance more accurately than a microsensor when the pile penetrates into the soil. In this paper, the pile installed full-size pressure sensor was used for penetration test and the relationship between formation parameters and pile tip force is obtained. Using the solution of the Kelvin problem in infinite space and the plane stress distribution function, the analytical solution of the bearing capacity of the soil plug is derived under the condition that the displacements of the bottom of the pile and the soil plug are consistent. The results show that the ultimate stress of the soil plug is closely related to the pile diameter and pipe thickness. The bearing capacity of the soil plug is closely related to the properties of the soil layer. The analytical solution of the bearing capacity of the soil plug has a linear relationship with the formation parameters SPT and CPT. The analytical solution of the ultimate bearing capacity of the soil plug has been verified by field test data and has a good match with the geometric dimensions of the pile tip and the formation parameters.

Prestressed high-strength concrete (PHC) pipe pile with the static press-in method has been widely used in recent years. The generation and dissipation of excess pore water pressure at the pile–soil interface during pile jacking have an important influence on the pile’s mechanical characteristics and bearing capacity. In addition, this can cause uncontrolled concrete damage. Monitoring the change in excess pore water pressure at the pile–soil interface during pile jacking is a plan that many researchers hope to implement. In this paper, field tests of two full-footjacked piles were carried out in a viscous soil foundation, the laws of generation and dissipation of excess pore water pressure at the pile–soil interface during pile jacking were monitored in real time, and the laws of variation in excess pore water pressure at the pile–soil interface with the burial depth and time were analyzed. As can be seen from the test results, the excess pore water pressure at the pile–soil interface increased to the peak and then began to decline, but the excess pore water pressure after the decline was still relatively large. Test pile S1 decreased from 201.4 to 86.3 kPa, while test pile S2 decreased from 374.1 to 114.3 kPa after pile jacking. The excess pore water pressure at the pile–soil interface rose first at the initial stage of consolidation and dissipated only after the hydraulic gradient between the pile–soil interface and the soil surrounding the pile disappeared. The dissipation degree of excess pore water pressure reached about 75–85%. The excess pore water pressure at the pile–soil interface increased with the increase in buried depth and finally tended to stabilize.

In order to have a better understanding of the real contact area of granular materials, the white light interference method is applied to explore the real surface morphology of clay soils under high stress. Analysis of the surface profile indicates that there exists a support point height z0 with the highest distribution frequency. A concept of a real contact region (from z0 to z0 + d90; d90 represents the particle size corresponding to 90% of the volume fraction) is proposed by combining a surface profile with the particle size distribution of clay soil. It was found that under the compressive stress of 106 MPa–529 MPa, the actual contact area ratio of clay soil varies between 0.375 and 0.431. This demonstrates an increasing trend with the rise of stress. On the contrary, the apparent porosity decreases with an increasing stress, varying between 0.554 and 0.525. In addition, as the compressive stress increases, the cumulative frequency of apparent profile height (from z0 − d90 to z0 + d90) has a concentrated tendency with a limited value of 0.9.

In this study, we reported facile synthesis of Fe3O4/C composite and its application for the cost-effective and sensitive determination of tryptophan (Trp) in human serum samples. Fe3O4/C composites were prepared by a simple one-pot hydrothermal method followed by a mild calcination procedure, using FeCl3∙6H2O as Fe3O4 precursor, and glucose as reducing agent and carbon source simultaneously. The Fe3O4/C composite modified glassy carbon electrode (Fe3O4/C/GCE) was prepared by drop-casting method. The microstructure and morphology of Fe3O4/C composite was characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Due to large specific surface area and synergistic effect from Fe3O4 nanoparticles and carbon coating, Fe3O4/C composite showed excellent electrocatalytic activity toward the oxidation of Trp. As a result, the proposed Fe3O4/C/GCE displayed superior analytical performances toward Trp determination, with two wide detection ranges (1.0−80 μM and 80−800 μM) and a low detection limit (0.26 μM, S/N = 3). Moreover, successful detection of Trp in human serum samples further validate the practicability of the proposed sensor.

To improve the accuracy of predicting the bearing capacity of offshore large-diameter monopiles, the initial high strain detection and repeated high strain detection with an interval of 10-84 days were carried out on 6 large-diameter monopiles with a diameter of 7.2m-7.4m in the offshore wind field dominated by clay soil layer. The results show that the time-dependent increment of tip resistance, side resistance and the total resistance of large-diameter monopiles in the same offshore wind farm has great discreteness, and the axial force increment of monopiles has a consistent change trend. This paper puts forward the prediction interval of 95% guarantee rate of bearing capacity increment of the offshore large-diameter monopiles based on depth, which provides a basis for the design of large-diameter monopiles. [ABSTRACT FROM AUTHOR]

Based on an analysis of the development of economic decision support systems, agents are applied to construct intelligent economic decision support systems. This paper proposes a task-oriented agent design concept and designs multiple types of agents to complete the decision-making tasks with the task as the core. The structure of multi-agent based systems is provided, and the concrete realization structure of different types of agents in the system is also provided. Additionally, this study discusses the operational mechanism of the whole system and the cooperation between multiple agents in the system. Finally, these functions are implemented through a combination of VC++ 6.0, multi-threading technology and the expert system tool CLIPS. The economic decision support system combines complex system theory, decision theory, information collection, knowledge discovery technology, economic decision making and simulation technology. It can aid users in making decisions by using communication and cooperation between multiple agents. [ABSTRACT FROM AUTHOR]

In order to explore the relationship between the critical bearing capacity and settlement of closed pile tip pierced into the soil, based on the Boussinesq solution and the Kelvin solution, the analytical solution between the critical bearing capacity and the critical settlement of the closed pile tip is derived by combining the stress distribution function. The analytical solution of critical bearing capacity and settlement of pile tip is verified by field test of static pressure pile penetrating into layered soil with a full-section pressure sensor installed at pile tip. The results show that during the penetration process, the bearing capacity increase stage of the pile tip is divided into linear steepening section and nonlinear slow increasing section. The soil in the linear steep increase section behaves as an elastic state. The bearing capacity of the pile tip before the punctured soil layer is linear with the settlement, and the final value of the linear steep increase section is the elastic limit value and the critical bearing capacity of the piercing pile tip. When the residual pile tip force is not considered, the critical settlement of the pile tip is between 0.095-0.119d; when considering the residual pile tip force, the critical settlement is between 0.091-0.105d. In particular, when the Poisson's ratio is 0.5, the analytical solution of the semi-infinite space is equivalent to the analytical solution of the infinite space. [ABSTRACT FROM AUTHOR]