应用干孔声波法测试隧洞围岩松弛圈

由于工程岩体受爆破、机械开挖、松动卸荷等诸多因素的影响,使得隧洞围岩内部的应力重新分布,在隧洞围岩表层出现应力释放区,该区如不及时进行处理或加固,很容易形成松动而破坏。因此,正确认识和测定隧洞围岩松弛变化特征,对工程开挖、灌浆补强以及隧洞洞室稳定程度评价具有重要意义。介绍了隧洞围岩松弛圈测试的声波法基本原理、方法技术及成果分析,应用干孔声波法测试取得声波纵波速度随孔深的变化曲线,通过分析隧洞围岩松弛圈、应力集中区和原岩的弹性波速特征,确定围岩松弛圈厚度范围,为隧洞稳定性评价及支护设计提供科学依据。

采用群孔疏干降水法穿越流砂层的施工技术

通过具体的施工实践 ,较详细地论述了群孔疏干降水法加板桩法施工技术的细节和注意事项 。

Research on 3D marine electromagnetic interferometry with synthetic sources for suppressing the airwave interference

In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient （RAC） of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.

挤压劈裂灌浆技术在锚杆施工中的应用

在广园路加压站边坡支护永久性锚杆施工中,应用了挤压劈裂灌浆技术,大大提高了锚杆的张拉力和土层的承载能力。

Numerical simulation and validation of ocean waves measured by an Along-Track Interferometric Synthetic Aperture Radar

A new nonlinear integral transform of ocean wave spectra into Along-Track Interferometric Synthetic Aperture Radar （ATI-SAR） image spectra is described. ATI-SAR phase image spectra are calculated for various sea states and radar configurations based on the nonlinear integral transform. The numerical simulations show that the slant range to velocity ratio （R/V）, significant wave height to ocean wavelength ratio （Hi2）, the baseline （2B） and incident angle （0） affect ATI-SAR imaging. The ATI-SAR imaging theory is validated by means of Two X-band, HH-polarized ATI-SAR phase images of ocean waves and eight C-band, HH-polarized ATI-SAR phase image spectra of ocean waves. It is shown that ATI-SAR phase image spectra are in agreement with those calculated by forward mapping in situ directional wave spectra collected simultaneously with available ATI-SAR observations. ATI-SAR spectral correlation coefficients between observed and simulated are greater than 0.6 and are not sensitive to the degree of nonlinearity. However, the ATI-SARoPhase image spectral turns towards the range direction, even if the real ocean wave direction is 30. It is also shown that the ATI-SAR imaging mechanism is significantly affected by the degree of velocity bunching nonlinearity, especially for high values of R/V and H/2.

Study of the location of testing area in residual stress measurement by Moiré interferometry combined with hole-drilling method

This paper investigates the effect of the location of testing area in residual stress measurement by Moiréinterferometry combined with hole-drilling method.The selection of the location of the testing area is analyzed from theory and experiment.In the theoretical study,the factors which affect the surface released radial strainεr were analyzed on the basis of the formulae of the hole-drilling method,and the relations between those factors andεr were established.By combining Moiréinterferometry with the hole-drilling method,the residual stress of interference-fit specimen was measured to verify the theoretical analysis.According to the analysis results,the testing area for minimizing the error of strain measurement is determined.Moreover,if the orientation of the maximum principal stress is known,the value of strain will be measured with higher precision by the Moiréinterferometry method.

Imaging algorithm for synthetic aperture interferometric radiometer in near field

With the benefits of digital IC technology development, the synthetic aperture interferometric radiometer (SAIR) technique is growing fast and expanding to more and more application areas. The near field imaging detection is a potential application which has received increasing demand recently. Because the Fourier imaging theory of the traditional SAIR is based on far-field approximation, it will be invalid for near-field condition. This paper is devoted to establishing a new accurate imaging algorithm for near-field SAIR imaging. Firstly, the visibility function in near field is deduced and the relationship of which to far-field visibility function is analyzed. Then, a numerical method based on pseudo inverse and focal plane approximation is developed. The effectivity of this method is tested with imaging simulation of point source and extended source, and the superiority is also demonstrated by comparing with the existing phase-modified Fourier transform method. At last, the field experiment with one-dimensional SAIR instrument is performed to validate the practical feasibility of this method.

A novel high birefringence equal diameter circular-hole photonic crystal fiber

A novel equal diameter circular-hole photonic crystal fiber(PCF) with high birefringence is proposed and numerically analyzed by employing the finite-element method. The proposed PCF's birefringence is 10^(-3), which can reach 2 orders higher than that of traditional high birefringence fiber, and this equal diameter circular-hole structure reduces the difficulty of the actual drawing process. The effect of different parameters on the birefringence of this PCF is investigated, and the application of the Sagnac interferometer based on fiber filling technology in temperature sensing is studied. The result shows that the high birefringence PCF can be used in both optical communication and optical sensing fields.