地基

Based on the stress mechanism with composite foundation and rigid foundation,and the accuracy grade of pile positioning,the author believes that the existing technical standards for pile displacement in soil-cement mixed pile foundation are unreasonably rigorous.

基于复合地基和刚性桩基的受力机理、桩的定位精度分析，认为规范中对水泥土搅拌桩地基的桩偏位规定过于苛刻，参照混凝土灌注桩及其他复合地基桩偏位规定，提出对水泥土搅拌桩偏位作适当修正。

The soil and cement are mixed into a solidified body in the deep level of the foundation by special-purposed deep mixer with cement as the solidifying agent, it can be increase the bearing capacity and decrease the settlement of the foundation by using the deep mixing method.

深层搅拌桩是一种加固饱和软粘土地基的一种方法，它是利用水泥、水泥浆、石灰等材料作为固化剂的主剂，通过特制的深层搅拌机械，在地基深处就地将软土和固化剂强制搅拌，利用固化剂和软土之间所产生的一系列物理-化学反应，使软土结硬成具有整体性、水稳定性和一定强度的良好地基。

The soil and cement are mixed into a solidified body in the deep level of the foundation by special-purposed deep mixer with cement as the solidifying agent, it can be increase the bearing capacity and decrease the settlement of the foundation by using the deep mixing method .

深层搅拌法是以水泥作固化剂，通过专用的深层搅拌机械，在地基深部就地将土和水泥搅拌而成加固体，应用该法处理地基可增加地基承载力，减小沉降。

In this paper, the fundamental theories and general development situation of composite foundation had been summarized at first. By comparing the application effectiveness and economical efficiency of several major piles types used in soft soil area, it was been indicated that these piles types were all defectively on bearing capacity or economical efficiency, while the rigid-flexible, long-short pile composite foundation could make full use of its bearing capacity, reduce the quantity of piles, and satisfy settlement and bearing capacity requests.

本文首先综述了复合地基及复合桩基的基本理论和发展概况，通过对深厚软土地区几种常用桩型应用情况及经济性能的比较，指出现行的几种常用桩型都不同程度地在承载能力或经济性上存在一定的缺陷，而通过比较表明刚柔性长短桩复合地基能最大限度的发挥复合地基的承载力，以减少用桩量，并满足工程对沉降和承载力的要求，因此，具有良好的经济性。

The results of numerical analysis show that the elastic modular and the poisson ratio have no effect on two-dimensional bearing capacity, but can affect the ultimate bearing capacity of three-dimensional foundations and control the convergence and precision of finite element calculation; the earth pressure coefficient controls the geostatic stress of foundation, sequentially affects the ultimate bearing capacity of foundations and the convergence of numerical calculation. When calculating the ultimate bearing capacity of undrained saturated foundation, the complete formulation exists shear locking, and reduce formulation exists hourglassing, so the hybrid formulation is suitable to imitate the geomaterial. When the soil obeys nonrelevent flow rule, the yielding function is different from potential function, and the elastic-plastic matrix of soil is asymmetric, so the unsymmetry numerical solver and appropriate finite element mesh is required.

研究结果表明，土体弹性模量和泊松比对二维基础极限承载力没有影响，但是影响着三维矩形基础的极限承载力，控制着ABAQUS数值算法的计算精度与收敛速度；地基土压力系数控制着地基土体中的地应力平衡，从而影响着二维条形基础和三维矩形基础的极限承载力和地基破坏包络面；对于不排水饱和软黏土地基，常规的完全积分单元会造成剪力自锁现象，而减缩积分单元则存在过于柔化的现象，故采用杂交单元来模拟较合适；当土体服从非关联流动法则时，屈服函数与塑性势函数之间存在差异，从而导致土体弹塑性矩阵呈现非对称性，在有限元计算中必须采用非对称数值解法，并且合理地划分单元才能对极限承载力进行准确求解。

A number of calculation examples, including past experiments, our experiments, thick slabs experiments, thin slab experiments, single slab experiments and doweled slabs experiments, are given. By comparing test values with calculating values, some significative conclusions are drawn. The superiority of generalized conforming element for thick-thin slab on foundation is pointed out. The average ranges of foundation parameters are given according to these experiments.

6利用有限元程序进行正分析，用遗传算法进行反分析，识别地基的基本参数，实现地基参数的原位测试；给出大量算例，包括前人的试验和本文的试验、薄板与厚板、单板与接缝板，通过计算值与实测值的比较，得出一些较有意义的结论；阐明了双参数地基上广义协调厚薄板通用元的优越性并给出了试验场地地基参数的平均取值范围。

First this paper presents two-way seepage consolidation solutions of sand-wall ground, based on the assumption of equal strain boundary conditions. Second, comparisons of the solutions and Barons axisymmetric consolidation theoretical solutions are conducted to find an equivalent and matching method for plane strain analyses and axisymmetric analyses of sand-drained ground.

为了能用平面应变有限元来分析砂井地基，本文首先推导出了砂墙地基(砂井地基在平面应变条件下的表现形式)双向渗流等应变固结理论解，然后将此解与巴隆轴对称固结理论解相比较，得到砂井地基平面应变情况和轴对称情况之间的等效公式。

These problems include the selection of the pile styles, the application of the composition foundation of rigid piles with soft piles together, the computation of bearing capacity and settlement, the relation between the stress radio and bearing capacity, and the application of counter-construction using in composite foundation.

结合工程实践，在阐述刚性桩复合地基受力机理的基础上，对其设计中桩型的选择及其与柔性桩复合地基的综合应用、承载力与变形的计算、桩土应力比与复合地基承载力的关系以及逆作法施工桩基在复合地基施工中的应用等问题作了探讨。

Based on the efficient approach developed above, cases of foundationinhomogeneity with stiffness varying according to an exponential function along the radialdirection, and cases of foundation inhomogeneity with stiffness discontinuity and with weakinterlayer strata on the earthquake response of concrete arch dams as well as gravity damswere analyzed. It is found that taking into account the effect of foundation inhomegeneity forthe earthquake safety assessment of concrete arch and gravity dams has great significance.

在以上理论的基础上，本文充分利用比例边界有限元法能够模拟非均匀无限域的优点，合理地提出了重力坝、拱坝的非均匀无限地基模型，分别研究了地基材料弹性模量沿深度按指数变化的无限不均匀地基和地基中存在断层或软弱夹层时对重力坝和拱坝的地震响应影响。

The study on Rayleigh wave characteristics in layered soil shows that shear wave velocity of soil can be attained.

许多学者对瑞利波在地基中的传播特性的研究表明，瑞利波能够反演地基土的剪切波速度，而剪切波速度跟地基土特性又有联系，因此，可以利用瑞利波法来反演地基土的特性。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。