What are the principles and characteristics of the classification and layout of the construction con

Answer]: This question mainly assesses the concept of engineering construction control network and its layout method. Usually, different stages in the process of engineering construction need to implement various positioning work through measurement, for the laying of construction control network, the general requirement is to control the hierarchical distribution network step by step, and meet the accuracy and density requirements.

When the hierarchical layout is placed, the first level is the overall control, and the secondary level is the lofting service. In the option, the control network layout adopts multi-level or hierarchical arrangement, and it is incorrect to carry out overall control or cross control, and it is incorrect to implement multi-level control, which is not divided into levels, so the answer should be c.

Answer] :d This question mainly examines the basic principles of construction surveying, and at the same time examines the candidate's ability to analyze the problem and identify the ability, which has a certain degree of difficulty. Construction surveying is a regional work, so it must be carried out step by step from the overall scope involved.

In order to meet the overall consistency of the construction surveying work, and to overcome the residual cavity impact caused by the propagation and accumulation of errors on the measurement results, the construction surveying work should generally follow the following principles:

1) Procedurally compliant"From the whole to the part"requirements;

2) The steps of implementation are:"Control first and then detail;

3) Accuracy requirements"From high-level to low-level rent"。

By analyzing the four options, it can be concluded that the correct option for this question is D.

Summary. Hello, dear. We're happy to answer your <>

The basic principle of control network layout is to hierarchical without step-by-step control, 1, triangulation network wire network laying principle, hierarchical networking, step-by-step control, with sufficient accuracy, sufficient density to have a unified specification 2, the principle of horizontal network laying, from the high to low, from the whole to the part, step-by-step control, step-by-step encryption 3, the principle of engineering control network laying, to have enough precision and reliability, to have enough point density, to have a unified specification.

The basic principle of the layout of the control network is that there is no hierarchical control, in which the reference network is laid into what kind of wire network.

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Hello, dear. We're happy to answer your <>

The basic principle of the control network layout is that there is no step-by-step control of the landside classification, 1, the principle of triangular network wire network laying, hierarchical networking, step-by-step control, with sufficient precision, with enough density to have a unified specification 2, the principle of horizontal network laying, from the high-level early sale oak to the low-level, from the whole to the part, step-by-step control, step-by-step encryption 3, the principle of engineering control network lay-out should have enough precision and reliability, there should be enough point density, and there should be unified specifications.

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Dear, <>

It is a pleasure to answer for you how to ensure the implementation of the principle of the control network, <> the principle of the layout of the control network to ensure its implementation (a slag Zheng seepage) construction control network is during the construction of the survey engineering building service, its layout should be based on the general design drawing and the general construction drawing, such as the conditions of the ridge field unified consideration. (2) When laying out the construction control network, it is necessary to consider the overall requirements of the construction site (absolute accuracy) and the local requirements of the building (relative accuracy). When the area of the construction area is not large or the buildings with local accuracy requirements are concentrated, the scheme of comprehensively improving the accuracy of the entire construction control network can be considered.

At this time, the accuracy of the control network is usually designed with the local accuracy of the highest building cluster thickness, when the area of the building area is large, or the first level network with the accuracy of the main axis of the local fine building (absolute accuracy), the secondary network (independent network, the local accuracy is higher than the first level network) that meets the requirements of local accuracy (relative accuracy) is encrypted. (3) The location of the control point should be well visible, easy to use, try to avoid construction interference and facilitate long-term storage. (4) The location of the building on the general design plan is often represented by the construction coordinate system (or the building coordinate system), or the axis of a major building is the coordinate axis of the construction coordinate system, and the coordinate system of the construction control network should be consistent with the coordinate system of the general design drawing.

When the construction coordinate system is released from other coordinate systems, the coordinate conversion relationship should be given.

Control networks are divided into two categories according to their different uses: national basic control networks and engineering control networks.

The main role of the National Basic Control Network is to provide uniform coordinates across the country; The engineering control network is a special coordinate control network laid out for a certain project, which is divided into mapping control network, construction control network, deformation monitoring network, etc.

The mapping control network is a mapping control network established in the survey and design stage before the construction of the project, and its purpose is mainly to serve the surveying and mapping topographic map, which does not consider the overall layout of the engineering building and does not consider the overall layout of the engineering building, so it can not meet the needs of the subsequent engineering construction in the point release and density.

The point density and accuracy of the construction control network depend on the nature of the construction, and the accuracy of the construction control network is generally higher than that of the mapping control network, and has the characteristics of small control range, large density of control points, high precision requirements, and large interference by construction.

First, the form often used:

The plane control network of the site can be laid out into the form of building grid, wire and wire network, triangular network or GPS network according to the topographical conditions of the site and the layout of buildings (structures).

Second, the main points of the plane control network:

1. The plane control network of the site area should be laid out according to the scale of the project and the needs of the project For the construction site of more than 1km square engineering projects or important industrial areas, a plane control network of one or more accuracy levels should be established; For engineering projects or general construction areas with a site area of less than 1km, a control network with secondary accuracy can be established. The positioning accuracy of the field plane control network relative to the control point in the survey stage should not be greater than 5cm

2. The location of the control network should be selected in a place with good visibility, easy to measure, and conducive to long-term storage, and the corresponding marking stones should be buried, and a forced centering device should be added if necessary. The burial depth of the marker stone should be determined according to the ground freeze line and the site design elevation.

The control network can generally be divided into two categories: the national control network and the engineering control network.

1. National control network.

A control network established throughout the country is called the National Control Network. It is the basic control of the various scale surveys in the country and provides research information for determining the shape and size of the Earth. The national control network is established by precision measuring instruments and methods according to the measurement accuracy according to the first, second, third, and fourth grades, and its low-level points are controlled by the high-level points step by step.

2. Engineering control network.

In a small area, the control network independently established on the basis of the earth control network is called the engineering control network. The function of the engineering control network is to control the three-dimensional position (plane position and elevation) of the construction in the area.