软土地基变形的混沌性与承载力识别

本文以混沌理论为基础, 分析了软土地基变形的混沌性态, 并采用映射函数f(x)=ax2+c来拟合软土地基的沉降-载荷曲线。根据映射函数的不动点, 对软土地基加固前后的承载力进行了识别, 并与按相对变形值确定的承载力进行了比较。     

发震断层面上潮汐有效剪切应力增量的计算与加卸载的确定

发震断层面上潮汐有效剪切应力增量的数值计算是应用响应比理论的一个关键性基础问题。本文根据潮汐形变理论及弹性力学理论，导出了直接、严密和实用的潮汐有效剪切应力增量的数值计算公式，给出了判断加载、卸载区间的直接公式——潮汐有效剪切应力增量对时间-阶微分的解析表达式，最后还给出了一些应用实例。     

加卸载响应比——一个刻划构造运动稳定性的新参数及其在地质灾害预测中的应用

加卸载响应比这一新的参数可以定量地刻划构造运动的稳定程度.非稳定的构造运动常引起地质灾害,所以测定与计算响应比就可能预测地质灾害.利用此方法进行了地震预测(后验性的与先验性的),均取得成功.     

中国大陆M2波理论应变潮汐模型

本文主要研究和讨论了我国大陆固体潮和海潮负荷效应的M₂波理论应变潮汐模型。推导了球扇波应变张量大地系数和计算公式,着重研究和计算了M₂波海潮应变负荷效应,讨论了计算方法,计算中采用了到目前为止最新的Schwiderski（M₂）全球海潮图和沈育疆近中国海潮汐图;给出了40个点的负荷效应结果,并绘制了中国大陆固体应变潮、海潮应变负荷效应同相位,相差π/2相位以及总效应的应变花。为理论研究,观测资料的分析和改正提供了理论参考模型。     

模拟引潮力作用下的岩石破裂特征──加卸载响应比理论的实验研究之一

根据加卸载响应比理论，选用纵波速度作为响应参数，在实验室内，在模拟构造应力和引潮力的共同作用下，使岩石失稳破裂．在整个过程中测量纵波在岩石中的走时或速度，发现加卸载响应比Ｙ的值，在系统稳定时近于１；而在失稳前，逐渐增加，最大可达到１０．实验结果和理论预测曲线非常相近．认为可用纵波速度的响应比来表示岩石系统的稳定程度．     

Undrained cyclic behavior of bentonite–sand mixtures and factors affecting it

In this work, the cyclic behavior of bentonite–sand mixtures and factors affecting it were studied by means of a ring-shear apparatus and a scanning electron microscope. It was found that bentonite content had a significant influence on the liquefaction potential of the studied soils. A small amount of bentonite in the mixtures would cause the formation of “loose” microstructures, resulting in the occurrence of rapid liquefaction under cyclic loading, while a high bentonite content would cause the formation of clay matrixes, thus raising the soil resistance to liquefaction. In addition, the effect of pore water chemistry on the cyclic behavior of a high plasticity bentonite–sand mixture was carefully examined. It was also found that the presence of ions in pore water would change the clay microfabric, making it more open and thus more vulnerable to liquefaction. Finally, the effects of loading frequency on the cyclic behavior of mixtures with different amounts of bentonite were investigated. It was found that as the bentonite content increased, the influence became more pronounced.     

Determination of Ocean Tide Loading Displacement by GPS PPP with Priori Information Constraint of NAO99b Global Ocean Tide Model

The published global ocean tide models show good agreement in deep oceans and exhibit differences in complex coastal areas, along with subsequent Ocean Tide Loading Displacement (OTLD) modeling differences. Meanwhile, OTLD parameters (amplitudes and phase lags) derived by Global Positioning System (GPS) Precise Point Positioning (PPP) approach need long time to converge to a stable state and show poor precision of S2, K1, and K2 constituents. Based on the fact that no constraint is imposed in the current kinematic solution, a new method is put forward, in which global ocean tide model predictions are taken as the priori information constraints to speed up the convergence rate and improve the accuracy of the GPS-derived OTLD parameters. First, the data of tide gauge from 01 January 2014 to 31 December 2016 are used to generate the harmonic parameters to evaluate the accuracy of six global ocean tide models and a regional ocean tide model (osu.chinesea.2010). Osu.chinesea.2010 model shows good agreement with the tide gauge results, while NAO99b model presents relatively large difference. The predictions from osu.chinesea.2010 and NAO99b model are employed as reference and the prior information, respectively. Second, continuous observations of 12 GPS sites during 2006–2013 in Hong Kong are collected to generate three dimensional OTLD amplitudes and phase lags of eight constituents using PPP with prior information constraints approach and harmonic analysis. Third, comparing the convergence time of eight constituents from PPP without and with priori information constraints approaches, the results show that the new method can significantly improve the convergence rate of OTLD amplitude estimates which obtain a certain level of stability seven years earlier than that derived by the PPP without priori information constraints. Precision of OTLD parameters derived by the new method is about 1 mm. By comparing with the precision of single PPP approach, the accuracy of eight constituents has been improved, especially for S2, K1, and K2 constituents. Finally, through comparing the different correction effects of OTLD estimates on the coordinates and their time series of the ground GPS stations, the results show that OTLD estimates derived by the new approach have similar influence as the osu.chinasea.2010 ocean tide model. The new method provides an effective means to improve the convergence and precision of the GPS-derived OTLD parameters, and achieve a similar correction as the high precision ocean tide model.     

横向非均匀地球负荷问题的CLFE有限元算法的有效性

本文设计了三个数值算例分别模拟径向分层黏弹地球对二阶球谐负荷、均厚圆盘负荷和全球末次冰期真实冰负荷的响应.利用耦合位扰动Laplace方程的三维有限元法(CLFE),计算出地球表面的位移、大地水准面的变化、冰后海平面变化和这些量的现今变化速率,并将其结果与传统谱方法的结果进行对比.结果表明,两种方法的结果总体上表现出良好的一致性,因此,CLFE方法被证实是正确的、有效的、能被用于研究地幔横向非均匀性的影响.值得注意的是,新的方法完全没有横向非均匀小扰动假设的限制.     

重力潮汐改正

高精度重力测量迫切要求提高重力潮汐改正的精度,本文应用现有的我国重力潮汐观测成果和海潮重力负荷改正计算结果,提出一组重力潮汐改正的实用计算公式。并且根据计算误差要求小于±1μGal的条件下,将我国划分为四个区,与合适的计算式相对应。此外,对近年来国外学者所提出的理论重力潮汐改正计算公式进行了评述,尤其对过去不曾注意的潮汐永久项（M0S0波）在潮汐改正中的影响进行了较详细的讨论。最后还对目前海潮负荷改正的精度提出了一些看法。     

循环荷载下土石混合体力学特性野外试验研究

土石混合体是一种物理、力学性质非常复杂的不连续介质。以云南某高速公路土石混合体边坡为例,分别对选取的3个试验点进行了单调加载、循环加载一次及多次循环加载试验,获取了其相应的剪切位移-剪切应力关系曲线,并对其曲线特征进行分析研究。通过对试样三维滑动面的形态分析,指出由于土石混合体三维滑动面的不规则性,利用传统的二维计算方法难以得到较为准确的强度参数。基于三维极限平衡理论,提出了土石混合体水平推剪试样强度参数的三维数据计算方法。并利用该方法得到了研究区土石混合体的相应的强度参数及残余强度参数。