控制参数

控制参数是什么意思？

Control parameters are factors that affect the selection of trenchless pipe installation methods. Trenchless construction techniques adopted for a particular project are determined based on many parameters including the latest geotechnical investigative reports, and existing records. This helps design the most suitable route with minimum cost and time overruns.

围绕特定参数仔细设计了水平定向钻孔（HDD），水平螺旋钻孔（HAB）或微管钻等特殊的建筑项目。这些参数包括土壤条件，岩石的存在，土壤层的变化，以及通过计划路径的现有公用事业结构的存在。

Trenchlesspedia Explains Control Parameter

Control parameters become the controlling factor in the design of a route and selection of a method that is least obstructive and most economical. These parameters are determined based on an extensive geotechnical investigation that helps contractors to decide the most suitable method, rig, cutter head, or drill bit that will be required to carry out the project successfully. Some crucial control parameters include:

岩土考虑因素

Every project has a unique site and soil conditions with regards to surface and subsurface conditions. The surface investigation is necessary to obtain information about the area, elevation, existing structures, borehole locations, and environmentally sensitive areas such as wetlands.

The subsurface investigation is carried out to gain information about the type of soil, depth of bedrock, water table, etc.Test pits, boreholes, ground-penetrating radar (GPR), etc. are used to obtain the same and it also includes data from previous site investigations and existing records.

安装深度

土壤条件在很大程度上决定了安装深度。对于HDD项目，由于跟踪系统限制和进入和出口轴不存在，建议最大挖掘深度限制为160英尺。

Drive Length

项目中涉及的风险随着安装长度的增加而增加。由于安装的长度和复杂的土壤条件，需要更多的驱动力。最大驱动力将取决于设备的容量，但由于动员和复员设备的高成本，最小的驱动长度必须经济地是经济合理的。

Pipe Diameter and Pipe Material

管道直径也是控制无齿板的选择的重要参数。例如，HDD和HAB的推荐直径为12至48英寸，而其他方法如管道，和微管钻可用于安装较大的直径管道。

The pipe material also is a necessary factor as pipes made of高密度聚乙烯（HDPE），聚氯乙烯（PVC）和玻璃化粘土管（VCP）不能用于HAB，管道和管道撞击等方法.

管道类型

HDD仅限于压力管道应用，而Microtunneling仅限于重力应用。HAB和管道千斤顶可用于压力和重力应用。

发射和检索轴

Entry and exit shafts are needed for all trenchless methods except HDD. The dimensions of these shafts will depend on factors such as equipment size, drive length, pipe length and diameter, thrust system, and spoil removal system.