InPart 1我们的博客系列电竞app竞猜我们讨论了不同类型的深层基础，其中一些进入他们的设计。一旦选择了深度基础系统并确定了负载要求，就开始构建它们的过程。在这篇文章中，我们将专注于与深层基础相关的质量控制和完整性测试。

成功的深基础项目包括质量计划，以验证设计假设，并确定承包商是否可以按计划安装深基础。对于大多数项目，质量计划围绕两个不同的操作程序构成：观察和测试。

Observations

Observations have been a part of deep foundation quality programs for as long as deep foundations have been around. In many cases, they provide some of the most useful information to the design team in evaluating the abilities of individual deep foundation elements to meet the design requirements. Unfortunately, observations often do not explain why something occurred, but only give the result, such as a high grout-take for a portion of an auger-cast pile, or a driven pile having a sudden decrease in penetration resistance. Hopefully, the geotechnical engineer has gathered enough information from the design or even the construction phase of the project to interpret the observation results in a meaningful manner.

建设深基础系统期间的具体观察因系统而异。通常，观察结果包括相对于设计深度/高度，耐驾驶或钻孔的安装深度/高度，以及如何拆除桩顶的量度。对于钻井基础，除了测试灌浆或混凝土以进行一致性和强度之外，还观察到相对于钻孔量的混凝土或灌浆的量。可以观察到钻孔轴的底部以记录脚趾将承受声音材料。

类似地，通常会观察到从动管桩造成损坏，扫描和/或水的指示。随着技术的近期进步，大多数观测结果由电子记录设备补充，可以计算驱动基础的打击次数，记录螺旋铸造桩的深度，灌浆容积和压力以及许多其他数据。但是，计算机还无法录制建筑的每个细节。因此，在安装深层基础期间需要人类观察者。

Load Tests

由于相关成本，负载测试通常仅在测试桩上执行，而且还可以偶尔在生产桩上执行。一些负载测试是破坏性的。破坏性负载测试是一种可能损坏深基础的测试，或者显着改变支持深层基础的土壤或岩石。在任何一种情况下，测试桩可能无法在测试之后设计，并且这样的测试桩被牺牲并且不纳入支撑结构的基础系统中。

Other tests are non-destructive. A non-destructive load test is a test that allows evaluation of the resistance and structural strength of the deep foundation, while also allowing the deep foundation to meet the project requirements for performance after the test. A deep foundation subjected to a non-destructive test can still be used to support the structure.

有不同类型的负载测试,甚至different purposes for performing them. Static load tests can be performed by applying the load to the top or bottom of the deep foundation. The load type(s) and magnitude(s) applied to the test pile determine if a static load test is destructive or non-destructive. Most static load tests are done with the intent of determining the ultimate resistance of the deep foundation, so this type of test is typically considered a destructive test.

仅通过在深基础顶部或附近应用负载来执行动态负载测试。与静态负载测试类似，根据负载类型和幅度，动态负载测试可能或可能不会破坏性，但确定也取决于深基础的类型。然而，大多数动态测试是非破坏性的，因为只有一部分设计负载作为力的深基础。

对于将负载施加到顶部的静载荷测试，需要某种形式的反应系统（通常通过梁连接的堆）施加负载。主光束以测试桩为中心，液压插孔和称重传感器放置在梁和桩的顶部之间。桩顶被仪表以测量偏转，因此可以评估深基础的终极承载能力。在桩的底部施加负载最常使用与液压千斤顶类似的Osterberg电池（O-Cell），并包含用于测量O-Cell膨胀和菌株的仪器。

This approach does not require a reaction system as the skin friction of the deep foundation provides resistance to testing the end bearing of the deep foundation and vice versa. Like a top-load test, the top of the deep foundation is instrumented when applying the load to the bottom of the deep foundation, to evaluate the foundation’s ultimate load-carrying capacity. For either case of applying the load to the top or bottom of the deep foundation, instrumentation at different locations can be installed along the deep foundation length to allow evaluation of the skin resistance provided by different soil or rock layers.

动态载荷试验包括通常由滴重或动力驱动的锤子施加的冲击载荷，如柴油锤用于安装驱动桩的柴油锤。它们还可以使用质量和爆炸来在通常被称为准静态负载测试中创造力脉冲。最常见的是，通过测试设备 - PDA（桩驱动分析仪）引用动态测试，用于高菌株，全动态测试或司动力学，用于高应变，准静态负载测试。两种类型的测试都需要数值方法来确定不同桩段和桩脚趾提供的整体深层电阻和电阻。

From a geotechnical engineering perspective, performing a load test to failure using instrumentation is most useful. This approach allows us to obtain the most information from the load test and can result in reducing the overall deep foundation length either by lowering the safety factor (or increasing the resistance factor for LRFD methodology), or by using higher shaft resistance values or end bearing resistance values.

当然，载荷试验总是可能表明某些土壤或岩石层的估计在深基础系统的设计期间不提供尽可能多的电阻。通常具有保守的设计，这不会发生，但它可能发生。当估计电阻时，沿深基础长度的仪器允许使用实际电阻值进行修订设计。The downside of performing a load test is that it often requires a robust (i.e., expensive) reaction system for a load applied to the top of the foundation, and the sacrifice of equipment needed to apply a load to the bottom of the foundation (which can also be expensive). There is also difficulty defining failure and the different criteria methods to do so. We might need a Part III to discuss that topic!

完整性测试

完整性测试通常与观察结果一起对生产桩进行。因此，完整性测试是非破坏性的测试，旨在帮助评估深基础的原始形状。雷竞技好Newbee赞助商Braun Intertec在钻孔的深度基础上进行完整性测试，因为驾驶桩到地面的行为是一种完整性测试本身的形式。使用深度基础使用的最常见的完整性测试是使用脉冲回波或瞬态响应方法的交叉孔声波测井和低应变测试。

交叉孔声波测井需要在轴内安装进入管。在灌浆或混凝土达到足够的强度之后，将换能器和接收器放置在管内。当换能器和接收器从管的底部一起升高，测量从换能器到接收器到接收器的换能器所需的时间。重复该过程，直到测试管之间的所有可能的换能器和接收器配对的组合。评估数据以确定声波的到达时间是否存在显着差异，这些波浪在深基础内表示异常。

Low-strain integrity tests are performed by attaching an accelerometer to the top of a deep foundation and hitting the top with a lightweight (1- to 8-pound) hammer with a special cap. The cap on the hammer lengthens the impact pulse so that it is suitable for integrity testing. The accelerometer then measures the pile response to the induced stress wave. A good test will show a clear toe reflection at the anticipated length.

However, numerous factors can influence the quality of the test and the results. These factors include soil resistance, material properties (strength, density, etc.), reinforcement within the deep foundation, and the length of the deep foundation. As a general rule of thumb, integrity testing is practical for deep foundations with a length that is about 30 times its diameter, (e.g., we can reliably test a 1-foot diameter deep foundation to a length of about 30 feet) although Braun Intertec team members have successfully performed tests on deep foundation lengths up to 60 times the diameter on multiple occasions.

Putting It Together

经验，这是它的精彩老师一再教导我们一个成功的项目从规划和设计开始，以良好的，质量的计划结束。我们可以知道承包商在地面下方建立的唯一“真实方式”是挖掘它，这突破了将其放在那里的目的。一个综合计划，包括详细观察，负载测试和适用的完整性测试，可以为我们提供足够的信息来应用我们对深基础系统的整体能力来满足项目要求的整体能力。

有关深层基础的更多信息，请联系Matt Glisson。