低能量强夯联合井点降水在某工业厂房软土地基处理中的应用

针对某工业厂房的地质条件和地基工程的设计要求，采用了低能量强夯联合井点降水的地基加固方案。并介绍了地基处理的设计方案，检测结果表明低能量强夯联合井点降水地基加固方案处理本厂房浅层软土地基是切实可行的。     

用真空预压法加固碱渣软土地基效果评价

真空预压法是一种成功的加固软土地基的方法，但用于加固碱渣软土地基在国内外尚属首次。本文通过天津碱厂碱渣软土地基加固现场试验，证明了该法加固后的碱渣土可以达到堆场地基承载力（８０ｋＰａ）要求，为大量处理碱渣提供了一条新的途径。     

塑料排水板与强夯联合加固法在沿海软土地基中的应用

介绍了应用塑料排水板法和强夯法对某集装箱堆场软土地基的处理,通过对地基处理前后的土性对比分析表明,该法达到了预期的处理效果,为以后处理类似地基提供一些参考。     

软土地基条件下公路工程施工技术应用

主要简单介绍了公路工程中软土地基的特征和施工难度,通过对现阶段软土地基条件下公路工程施工中存在的问题进行分析,探讨软土地基条件下公路工程施工技术应用的有效措施,并进一步实施案例分析,以明确软土地基对公路工程施工带来的影响,加强对软土地基条件的处理,改善公路工程地基状况,为公路工程的后续施工奠定扎实基础,充分发挥软土地基处理技术作用,从而保障公路工程施工质量,维护公路工程的安全性.     

堆载预压法加固软土地基室内试验研究

本文结合宁波—舟山港某港口堆场地基处理的工程实践,通过现场钻探取样、原位测试、室内试验等,对堆载预压前后场地上部软土的含水量、孔隙比、液性指数、压缩模量、三轴UU(cu、u)以及场地下部碎石土的压缩模量、动力触探指标等物理力学性质变化规律进行了探讨,分析了堆载预压法加固软土地基的作用机理。试验结果表明:预压处理后,场地上部软土的各项物理力学性质得到了显著的改善,下部碎石土层改善不明显,堆载预压处理软土地基效果显著。     

浅谈建筑工程施工中的软土地基处理技术

在建筑工程施工过程中,无可避免的会遇到软土地基的处理问题。本文首先从软土的工程性质出发,分析了软土地基的特点,介绍了软土的成因、分类以及软土地基存在的工程地质问题,并全面阐述了多种软土地基的处理办法以及每种办法的特点,总结了软土处理技术的现状。同时,论述了软土处理新技术的应用及发展前景。     

深厚软土地区地基处理方法的研究探讨

随着建设规模的日益扩大,一些工程无法避免软土地基选择另一个场地进行工程建设,因此选择合理的处理方法处理软土地基显得尤为重要.在工程施工阶段,对于软土地基,施工单位应采取有效措施防止沉降、单边膨胀和位移的发生,以保证工程整体质量的安全稳定.本文在分析建设工程深厚软土地基处理方法的基础上,分析了几种常见的基础处理方法,希望...     

上海港某矿石堆场深厚软土地基加固设计研究

结合上海港某大型矿石堆场工程,针对上部覆盖有一定厚度饱和疏松无粘性土的深厚软土地基,将新型整体式热熔塑料排水板引入到软土加固中,利用堆场运营时堆放的矿石荷载,提出了"浅层处理、矿石分级加载、自动监测和使用期调整"的分步地基加固设计思路及相应的具体设计参数,并推广应用到实际工程中。实测结果表明,加固获得了较好的工程效果。     

公路工程施工中软土地基处理技术研究

在高等级公路建设过程中,软土地基容易沉降,介绍了高等级公路软土地基沉降的危害,从软土路基沉降的特征以及软土路基处理的目的,提出对软土地基处理技术的相关问题与解决方案,指出应在不同的条件下合理采用软土地基处理技术,从而解决高等级公路软土地基沉降问题。     

粉喷桩加固软土地基施工监测成果分析与应用

为了确保软土地基上构筑物的安全稳定，采用粉喷桩对某软土地基进行了处理，并在施工过程中对其空隙水压力、沉降与侧向位移进行了动态综合监测，通过对观测结果的分析，确定了合理的施工控制标准，并对粉喷桩加固软土地基的效果进行了评价。     

堆载引起某厂房坍塌事故的初步分析

通过对超载作用下地基软土性状的研究 ,指出由长期堆载甚至超载引起邻近桩基较大的侧向位移和位移累积是上海某工业厂房屋顶坍塌的主要原因。文中采用改进弹性地基梁法对堆载邻近的桩基进行理论分析 ,并通过桩基沉降和侧向位移对桥梁等上部结构影响的统计分析 ,提出了堆载大小和桩基变位的控制标准     

Experimental investigations of pile loads and foundation settlements in tall large-panel buildings

Conclusions 1. During the process of settlement of pile foundations with and without gratings in the nine-story large-panel frameless buildings with transverse and longitudinal bearing walls, the loads were redistributed and equalized, which was a consequence of interaction between the relatively rigid building box and the pliant base of the foundation. 2. Field investigations of the actual pile loads in the foundations of the nine-story large-panel buildings made it possible to establish that the design pile loads exceeded the actual values by 12–16%. 3. The nature of the distribution of the forces in the elements of the pile foundations of the large-panel frameless buildings indicates the need for taking into account the pliancy of the soil base of the pile foundation and its joint operation with the constructional components of the building box for determining the pile loads and for designing the gratings as well as the wall panels with gratingless support. 4. In the pile foundations of the nine-story frameless large-panel buildings with load-bearing, frequently transverse walls of the type of Series 1-464D, with and without gratings on compressible soils, the loads in piles with equal rigidities of the soil bases can be assumed to act as uniformly distributed, as an approximation, in engineering analyses. In the case of different rigidities of the soil bases of the piles, the load on each pile can be determined as a force proportional to the corresponding rigidity. 5. The actual settlement of the pile foundation of the large-panel building on alluvial soils was greater by a factor of 5–6, and for the building on the clay soils of the Ufa floor it was greater by a factor of 15 in comparison with the settlement of a single pile constructed on the basis of the same static test results, under the same soil conditions, and for the same loads. Hence, the coefficient ζ recommended in the SNiP II-17-77 for transfer from settlements of individual piles in static tests to settlements of piles in foundations under long-term loading should be differentiated according to the soil type and state. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 8–10, March–April, 1982.     

Multifunctional combined foundations on permafrost soils

The writers examine the construction of multifunctional combined foundations on permafrost soils, as approved for strengthening the foundation system of an administrative-industrial building in Norilsk. Such foundations make it possible to control the building deformations developed as a result of increase in the pile loads or in the settlements of the piles due to decrease in their bearing capacity when the soil base temperature increases.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 26–28, September–October, 1992.     

Large‐scale shaking table test on pile‐soil‐structure interaction on soft soils

The two large‐scale shaking table tests of tall buildings on soft soils in pile group foundations are performed to capture the effect of the seismic pile‐soil‐structure interaction (PSSI) on the dynamic responses of the pile, soil, and structure. The two different model conditions are observed, including a fixed‐base structure and a structure supported by 3‐by‐3 pile group foundation in soft soil, representing the situations excluding the soil‐structure interaction (SSI) and considering the SSI, respectively. In the tests, the superstructure is a tall building with 12‐story reinforced concrete frame. The pile‐soil‐structure system rests in a shear laminar soil container, which is designed to minimize the boundary effects during shaking table tests. The two models are subjected to various intensity seismic excitations of Shanghai bedrock waves, 1995 Kobe earthquake, and 1999 Chi‐Chi earthquake events. According to the experimental and analytical results, SSI systems have longer natural periods than the fixed‐base structure. In addition, soft soil has amplification effect under smaller seismic excitations and isolation effects under larger earthquake intensities. The strain amplitude at the top of pile is large, and the strain at the middle and tip is relatively small. Whereas the contact pressure is small at the top of pile and large at the middle and tip. From the dynamic responses of the superstructure, it is found that the PSSI amplifies the peak displacements and interstory drifts of the structures supported by pile group foundations by comparing with the fixed‐base structure. Whereas the peak acceleration and interstory shear force of the structure are reduced considering seismic PSSI. The results show that the seismic SSI is not always favorable, however, it may increase certain dynamic responses of the structure. Consequently, the seismic SSI should be considered reasonably, providing insight towards the rational seismic design of buildings rested on soft soils.     

钻孔灌注桩承载力异常现象分析

列举了上海及周边地区 6个工程共计 19根钻孔灌注桩的静载试验情况 ,其中大部分桩的极限承载力出现异常现象。同一工程场地同一几何尺寸的桩 ,单桩极限承载力相差可达 10 0 %以上。分析表明 :施工机具、成孔时间、护壁清孔方式、桩身结构完整性、地下障碍物及重复加载方式均对单桩承载力有重要影响。如果施工工艺不合理 ,会导致单桩极限承载力偏低很多 ;超载预压后 ,粉土、砂土地基中的钻孔桩承载力会增加 ,在软粘土地基中则会减小 ;与旧基础相连 ,将使桩的承载力偏大不少。     

Influence of vertical loads on lateral response of pile foundations in sands and clays

Although the load applied to pile foundations is usually a combination of vertical and lateral components, there have been few investigations on the behavior of piles subjected to combined loadings. Those few studies led to inconsistent results with regard to the effects of vertical loads on the lateral response of piles. A series of three-dimensional (3D) finite differences analyses is conducted to evaluate the influence of vertical loads on the lateral performance of pile foundations. Three idealized sandy and clayey soil profiles are considered: a homogeneous soil layer, a layer with modulus proportional to depth, and two-layered strata. The pile material is modeled as linearly elastic, while the soil is idealized using the Mohr–Coulomb constitutive model with a non-associated flow rule. In order to confirm the findings of this study, soils in some cases are further modeled using more sophisticated models (i.e. CYsoil model for sandy soils and modified Cam-Clay (MCC) model for clayey soils). Numerical results showed that the lateral resistance of the piles does not appear to vary considerably with the vertical load in sandy soil especially at the loosest state. However, the presence of a vertical load on a pile embedded in homogeneous or inhomogeneous clay is detrimental to its lateral capacity, and it is unconservative to design piles in clays assuming that there is no interaction between vertical and lateral loads. Moreover, the current results indicate that the effect of vertical loads on the lateral response of piles embedded in two-layered strata depends on the characteristics of soil not only surrounding the piles but also located beneath their tips.     

超载预压结合塑料排水板在滨海地区软土地基处理中的沉降分析

滨海地区软土具有含水量高、压缩性大等特点,在这类地基上修建道路,沉降较大。本文以具体实例为依据,对超载预压结合排水板设计进行了沉降分析。     

乾泽园小区疏桩基础设计

以实际工程为背景 ,详细阐述了疏桩基础的设计计算方法 ,与普通桩基方案进行了对比分析 ,重点介绍了疏桩基础上基底宽度的确定、用桩数量的优化、桩土荷载分担比的选择、建筑物沉降量的影响因素和有效控制手段 ,并与工程的实测结果进行了对比分析 ,研究结果和实测数据可供参考。     

北京富尔大厦基础处理

北京富尔大厦基础根据上部传来的荷载及地质报告,受周边条件限制,采用了深浅基础相结合的形式。主楼基础一部分柱基座位于已建住总大厦地下室筏板基础之上,另一部分柱基与筒体基础采用新设灌注桩基与地下连续墙基相结合的深基础。地下车库部分采用筏板基础。经受力分析,有效地控制了基础沉降量与沉降差,满足建筑受力及功能要求。     

预压作用下软土固结蠕变及微观结构试验研究

为了揭示预压荷载作用下软土路基工后沉降的机理,开展了室内模拟真空、堆载以及真空—堆载联合预压加固软土的固结蠕变三轴试验及微观结构试验。分析了在三种不同的预压作用下土体固结蠕变性状的不同和微观结构的变化机理。结果表明:在三种不同的预压荷载作用下,固结过程中,是真空—堆载联合预压条件下土体的沉降量最大,其次是堆载预压,最小的是真空预压。蠕变过程的沉降量是堆载预压的最大,其次是联合预压,最小的是真空预压。预压荷载作用下土体的固结和蠕变具有耦合效应;微观结构参数的变化受预压加载方式的影响。微观结构参数的变化率与宏观物性参数的变化率有相似的性质。